Humanity needs Islam for its spiritual transformation. It needs Islam to live happily and successfully in this life. It needs Islam to find salvation in the life to come. Islam is the religion of truth and it guides to all that is good.
WHAT ISLAM BESTOWS TO HUMANITY?
Almost all moral or religious reform & revival movements prior to Islam emerged as reactions against existing orders. This explains as to why they were one-sided & failed to address all aspect of human life. For example, Taoism-a Chinese version of mysticism- taught a corrupt and vice-ridden China to neglect material pleasures. Confucianism-a middle of the road approach- was opposed to these principles and called upon those who had retreated to monasteries to seek spiritual purification and individual piety in and through the thicks of life & to establish a virtuous state and live a social life among the people. India's vast fertile land was invaded several times, which caused its religions to become very mystical. In addition, asceticism grew as a reaction against the previously prevalent luxury and debauchery.  Likewise Judaism was heavily this worldly in its approach. Christianity, on the other hand, particularly in the beginning, developed too much as an otherworldly religion. It was a revelation, as Jesus Christ himself emphasized, for a particular nation at a particular time and in particular circumstances, and so was not the final and complete Divine message.  Only Muhammad (PBUH) emerged a the last Prophet of God to reveal His truth. Before this, polytheism and other variants of disbelief were prevalent: Most of humanity did not believe in God, but associated other gods with Him.  As people measured not God with His true measure  , some believed that He had a son while others erroneously considered the angels to be His daughters. 
The Prophet Muhammad (PBUH) revealed the truth about God and uncompromisingly emphasized His oneness & Unity. With him, God perfected His religion and declared that the true religion with Him is Islam  and: therefore, whoso desires another religion than Islam, it shall not be accepted of him and in the next world he shall be among the losers  . God revealed that the message , the prophet of islam, brought was universal,  that he spoke only what was revealed to him, and that he did not speak on his own authority. We appointed for you a Messenger from among you so that he will recite to you Our signs, purify you, and teach you the Book, wisdom, and what you do not know.  Such facts were foretold by Jesus  and mentioned in the Qur'an  . Only purified souls can use science and technology to benefit humanity. If this fact is ignored, such knowledge can lead to death & distruction as we witnessed in the twentieth century. Only purified souls fully conversant with science and technology can lead humanity toward true happiness here and salvation in the here after. 
Any religion or system that lacks the principles of spiritual purity or the conditions of a virtuous social life cannot provide true happiness. As will be explained, Islam provides a complete guidance for our lives here and in the hereafter. Prophet Muhammad (PBUH) was sent as the blessing for all the worlds, and so there is no need to renew the Divine message through another Prophet-so long as we hold the eternal and uncorrupted Qur'an,  Â & Sunnah of the prophet (PBUH).
Islam presents for mankind an equitable, fair and complete system of life, for while it exalts the human spirit and prescribes ideal ethical and spiritual principles for man, it does not deny the importance of the material aspect of his life either.  It is rather a comprehensive way of life, spiritually and materially, in the conscience of the individual as well as in the behaviour of the society, and includes the principles of social rights and obligations in all dealings, whether they pertain to economics, politics or to international relations.  Some people contend that Islam, now 1,400 years old, is obsolete and outmoded and, that new guidance is required. Such an assertion is totally unfounded, for Islam was revealed by God as an eternal & final message of God to human kind. Further, the Qur'an assures us that not only the Qur'an was revealed by God Almighty but it would also be presented by Him. Those who think that Islam has had its sway once, and now it is futile to attempt its rebirth, are labouring under grave misconception. The effervescence of its wave-is still curling the waters as the consequences of the Islamic revolution are by no means exhausted. Islam is destined to prevail over all other religions. And this assertion & expectation of Qur'an is yet to be materialized in full. It will be realized nonetheless-with us o without us is a separate question.
Moreover, Islam is addressed to essential human nature, & so long as his nature remains the same & the guidance remain operative & effective. It is a modern illusion that everything is subject to change. Human nature show a beautiful balance between elements of permanence and change: Outward forms change, while fundamental principles, basic values, and essential human nature and needs do not.  Islam is the only religion that embraces all dimensions of life and possesses an established method that allows for the perennial evolution of human society in accordance with life's fundamental principles and permanent values.  It is an outlook which manifests itself in all shades of human behaviour. Thus the Islamic concept of social, political and moral order is more concrete and tangible than of any other religion. 
The Islamic concept of religion as a complete code of life has in fact spiritualized all aspects of human existence. It was hitherto thought that the spirit and matter are entities essentially opposed to each other. Religion is concerned only with the soul and has nothing to do with mundane activities of human body which gravitate him towards evil. The depravity of human nature, especially the supposed essential evil of the body, led to the absolute suppression of the whole sensual side of man. The idea of a religious man was that of an extremely detached &, unsocial being. To flee from the social order, and take up the solitary life is the presupposition of salvation. It is in absolute loneliness, isolated from all other human beings that the religious and pious man stands face to face with himself and with Allah.
Each person is composed of three parts-spirit, mind and body. Each of these needs to be satisfied. They are so interrelated, and their needs are so different, that neglecting one results in our failing to attain perfection. 
As we read in the Qur'an: Fair in the eyes of men is the love of what they covet: women, children, stored-up heaps of gold and silver, horses of mark, cattle and tillage.  Our physical make-up and individual characteristics produce certain inclinations, and we can neither avoid satisfying these lusts implanted in us by the Creator nor be able to get rid of them. This does not mean that people attempting to satisfy their lusts are free to do as they please or cannot overcome their inclinations. On the contrary, this means that we can change our inclinations by exercising our free will, and can control our lust, anger, and other emotions and then use them to propel ourselves along the path of perfection and wisdom. 
Islamic attitude towards the physical needs of a man can be well judged from the following Hadith. It is narrated on the authority of Abdullah b. 'Amr b. al'As that he was once asked by the holy Prophet (PBUH) whether it was correct that he observed fasts during the days and spend nights standing in prayer. Abdullah affirmed that. The Holy Prophet (PBUH) observed: Don't do that. Keep fast at times and break at times, offer prayer and go to bed also. Your body has a right upon you, your eyes have a right upon you, your wife has a right upon you, and your guests have also a right upon you.  Just as our physical body has its own pleasures and pains, our spirit has its own joys and ailments as well. Sickness hurts the body, while the physical well-being, health, and whatever is in harmony with its nature gives it pleasure. As for the spirit, its pleasures and diseases depend on whether or not the carnal soul has been purified. 
All of us want to reach happiness. The most consummate happiness is to embody and manifest the Divine Attributes and characteristics. The soul of a truly happy person develops by knowing and loving God.  True happiness cannot be reached or retained unless all of the soul's faculties and powers are purified and reformed.  Partial or temporary Reform or purification will not result in true happiness. Just as a body can be considered healthy only when all of its limbs and organs are healthy, people can attain perfect happiness only when freed from all evil-commanding animal passions preventing their ascension to higher realms.  Islam does not subscribe to soul-body dualism. Physical urges are an integral part of man's nature: not the result of the original sin, and therefore the demand of their burial is unnatural fraught with unnatural problems. Islam stands for their transformation, education & training in order to redirect them to better ends and ideals. Reason left to itself could be barren & impotent. It requires the concurrence of passions to be operative & effective. The order that Islam recommends is that our passions should be sub-ordinated to reason; while reason should be guided by revelation. We should never allow the passions to run wild. Piety in Islam does not consist in suppressing the demands of the body; it aims at coordinating them with the demands of the spirit in such a way that life might become full and righteous. The Muslims have been asked not to forbid themselves the use of the bounties of Allah.  "Say: who has forbidden the beautiful gifts of Allah, which He has brought forth for His servants? And the things, clean and pure, which He has provided for sustenance. My Lord forbids only indecencies such of them as are apparent and such as are concealed and sin and highhandedness without justice, and that ye associate with Allah that for which He has not sent down any authority and that you say of Allah what you know not. 
Self Purification does not mean eliminating desires and anger or destroying our reproductive instincts and capacity for self-defense, for such abilities are essential for our survival & continued existence. For example, we are endowed with intellect to see the distinction between the devil & the Devine. And we are endowed with freedom so that we could choose either of the two.
Islam does not condemn outright the appetites of man; it justifies them to the extent where a man can put restraint upon them and control them according to the moral consciousness and thus use them for spiritual development.  'O you apostles! Eat of things that are good and do what is right; of your good things I am cognizant'. 
We must express our powers and faculties in a balanced and moderate way so that they can perform their functions properly. Purifying and training the intellect brings knowledge and wisdom, purifying anger engenders courage and forbearance, and purifying passions and desires develop chastity. The moral virtues acquired by those moving toward perfection and the realization of true happiness are wisdom, courage, and chastity. 
Our earthly life covers social, political, and economic aspects as well as spiritual ones. Our worldly nature presses us to be obedient to our desires. History testifies that when the power seekers finally do attain power, they turn to tyranny & oppression and enslave the poor and the weak. On the other hand, God is All-Just and never approves of injustice and oppression. Thus the religion He revealed must-demands that our rulers must be conscious of the Day of Judgment. They must be fair & just & avoid cruelty & oppression. 
Muslims believe that the Qur'an is the word of God (Allah) as revealed to the Prophet Muhammad (peace and blessings be upon him). It serves as the source of the Muslim worldview - together with the Hadith and Sunnah - and contains all the guidance that we require to lead a good life, both as individuals & as members of an Islamic state. 
WHAT ISLAM OFFERS TO HUMANITY?
Humanity needs Islam for its spiritual transformation. It needs Islam to live happily and successfully in this life. It needs Islam to find salvation in the life to come. Islam is the religion of truth and it guides to all that is good. The Qur'an has mentioned in three places:
"It is He Who has sent His Messenger with Guidance and the Religion of Truth, to proclaim it over all religion, even though the Pagans may detest (it)." (al-Tawbah 9:33 see also al-Fath 48:28; al-Saff 61:9). The truth is also called Al-'Ilm or knowledge which is the opposite of Al-Zann (the conjecture) Allah says that most people follow conjectures (al-zann) or wild speculations.
"Were you to follow the common run of those on earth, they will lead you away from the Way of Allah. They follow nothing but conjecture: they do nothing but surmise."  "These are nothing but names which you have devised Âµ you and your fathers -- for which Allah has sent down no authority (whatever). They follow nothing but conjecture and what their own souls desire! And indeed there has already come to them Guidance from their Lord."  "But they have no knowledge about it. They follow nothing but conjecture; and conjecture avails nothing against Truth." 
When people do not follow Allah's guidance (al-Huda) they end up in error and go astray (al-dhalal). They wander. Today the humanity is in error (al-dhalal). There is corruption every where. There are those who do not know what is wrong and there are those who know what is wrong but they do wrong things. There are those who know what is right and they do not do right things. The whole world is sick with godlessness, immorality, racism, violence, injustice and oppression. The humanity needs God's guidance. We human beings have mind, soul and body. We live as individuals and in families and communities. We are confronted with life and death. We need a religion that satisfies all our needs and answers all our questions and queries.
Islam, if put to practice, satisfies our minds and souls and takes care of our physical needs. Islam, if translated into actions, brings balance between our individual needs and our social and collective concerns. Islam, if our profession is put to practice, provides success, felicity and happiness in this life and salvation in the eternal life.
Islam is the religion that is based on the true natural disposition or Fitrah of human beings. Islam culminates in the most authentic form the same religion that Allah gave to all His Prophets and Messengers. In brief Islam offers to humanity:
A clear, simple, sound and profound belief system and Guidance.
A balanced action plan, with clear principles that are suitable for all times and places.
A universal outlook with a worldwide community of believers and brotherhood of the faithful.
A clear and practical vision for success and happiness in here and salvation in the Hereafter. Let us elaborate these points a little further.
A clear, simple, sound and profound belief system and Guidance
a- Oneness of Allah: This is the most logical, rational and spiritual belief. It is simple, yet ultimate truth and desire of all human beings. Islam teaches that Allah is One, the Lord, Master, Creator with Most Beautiful Names and Attributes.
b- The Message of Islam is presented in a Book, the Qur'an. This book is most authentic. Nothing in this Book is falsified with the advancement of science & technology or our knowledge in general. Its message is clear and always fresh and contemporary.
c- With the message and the Book there is a human personality who is not mythological but historical. He was the ideal human being who lived the message and presented it to the people in the most beautiful and loving way.
Islam is Allah's guidance; it is He who has guided us to this way. Guidance is one of the most important themes of the Qur'an.
The Qur'an tells us that Allah created everything and He has guided everything: "Our Lord is He Who gave to each (created) thing its form, and further, He gave (it) guidance."  "Glorify the name of your Lord, Most High, Who created, then shaped in proper proportion; and he determined the way, then He granted guidance." (al-A'la 87:1-3) 
Allah has guided every thing by fixing its nature and ability. To human beings he also granted moral and spiritual guidance through His Prophets and Messengers.
Islamic guidance is for all humanity. Allah's guidance is for all people, in all places and at all times. Islam is the way to which Allah guided all human beings. This religion did not begin with Prophet Muhammad -peace be upon him. Islamic guidance is the same that came with the first couple of humanity when they arrived on this earth. When Allah sent Adam and Eve to this earth He told them: "We said: 'Get down you all from here: and if, as is sure, there comes to you guidance from Me, whosoever follows My guidance, on them shall be no fear, nor shall they grieve.'" 
Messengers and Prophets of Allah at different times and in different parts of the world received this guidance. This same guidance came to Noah, to Abraham, to Moses and to Jesus and then finally it came to Prophet Muhammad -peace be upon him and upon all the Prophets and Messengers of Allah. Allah says:
"That was the reasoning about Us, which We gave to Abraham (to use) against his people: We raise whom We will, degree after degree: for your Lord is full of wisdom and knowledge. We gave him Isaac and Jacob: all (three) We guided: and before him, We guided Noah, and among his progeny, David, Solomon, Job, Joseph, Moses and Aaron: thus do We reward those who do good: And Zakariya and John, and Jesus and Elias: all in the ranks of the Righteous: And Isma'il and Elisha, and Jonah, and Lot: and to all We gave favor above the nations: (To them) and to their fathers, and progeny and brethren: We chose them, and We guided them to a straight Way. This is the Guidance of Allah: He gives that guidance to whom He pleases of His servants. If they were to join other gods with Him, all that they did would be vain for them. These were those whom We gave the Book, and Authority, and Prophethood: if these (their descendants) reject them, behold! We shall entrust their charge to a new People who reject them not. Those were the (prophets) who received Allah's guidance: follow the guidance they received; say: "No reward for this do I ask of you: this is not but a reminder for the worlds." 
Allah has given us many sources for guidance.
Five senses: sight, hearing, taste, smell, touch all these guide us in our life and help us a great deal. It may be observed that the Quran has emphasized the eyes, the ears, & the hand & heart as the main sources of knowledge. Eyes stand for observational & empirical knowledge. Our ears stand for collective heritage of human kind. Our head is the source while our knowledge matures & we draw inferences for the future. Heart is the recipient of wisdom & values. It is the core of our being.
Reason: It is a gift of Allah. He gave human beings reason ('Aql) and made the 'Aql as a condition for all responsibilities. Reason and intellect help us in finding the right direction.
Intuition: Sometime we know things and are guided by our instincts & feelings without using senses or reason.
Revelation: This is the supreme and perfect source of guidance. It is a special gift of Allah that He gave to humanity through His chosen beings people who were the Prophets of Allah.
In Islam all these sources are recognized and respected. We thank Allah for our senses and consider them Allah's gifts. Islam is not against reason. Reason and revelation are not mutually contradictory but are mutually complimentary in Islam. Science and religion are also not incompatible in Islam. Islam does not say that we should suspend reason or dismiss science in order to become good believers. However, Islam does emphasize that our senses, our reason, and our intuitions or instincts though necessary are not sufficient sources to guide us. We need divine revelation & Prophetic guidance. Reason by itself, without the guidance of revelation, is prone to commit errors. Reason, senses or intuitions cannot guide us in metaphysical & eschatological matters, which provide us the true anchorage to our moral & spiritual life.
We need divine guidance. Allah's guidance is the real guidance:
"Say: 'The Guidance of Allah, that is the (true) Guidance.' Were you to follow their desires- after the knowledge which has reached you,- then you would find neither Protector nor Helper against Allah." 
Balanced Action Plan:
This action plan takes care of the individual, family and society. Its guidance is comprehensive, practical and balanced. It guides:
a- In the matters of worship - to establish deep and loving relationship with Allah.
b- In ethics and morality - it teaches discipline, moderation, virtue and goodness.
c- Laws and rules - it gives rules that are practical, dynamic and progressive. The rules are not rigid. They are practical and their purpose is not to burden us but to guard & guide us.
Islamic law gives us the knowledge, of our fundamental rights and obligations and of what is good and bad for humanity on the individual and collective levels. Thus the Islamic view of life consists of a set of rights and obligations by which Muslims are expected to follow. Broadly speaking, Islamic law deals with our life in terms of our relationship with our Creator, ourselves (our rights upon ourselves), other people, and our natural environment (the rights of the resources that God has given to us for our benefit). 
Muslims are urged to perform their daily prayers in congregation, and must do the same for the Friday noon congregational prayer. This creates a bond of love and mutual understanding, arouses a sense of collective unity, fosters a collective purpose, and inculcates a deep feeling of brotherhood and sisterhood. Prayers are a symbol of equality, for poor and rich, low and high, rulers and ruled, educated and uneducated, black and white all stand in rows and prostrate before their Lord. Furthermore, this gives a strong sense of collective discipline and obedience to the community's leader. Prayers train Muslims in those virtues that engender the development of a rich individual and collective life. 
Islam regards human beings as God's vicegerents and cannot tolerate the degradation brought on by their submission to humiliation or oppression, for Islam is the real way to freedom and liberation. It invites people to struggle against oppression and tyranny for their freedom and dignity. By prostrating before God, Muslims declare that they bow to no other power. Islam forbids serfdom; promises universal freedom, independence in thought, action, property, and religion; and safeguards a person's integrity, honor, and dignity. 
Islam frees people from their lusts so that sensual pleasure does not tempt and corrupt them. Consuming intoxicants and engaging in gambling, nightclubs, mixed social activities, overspending, conspicuous consumption, arrogance, greed, and so on are all humiliating factors that destroy a person's honor and dignity. Colonialists and imperialists used such practices to enslave Muslims and many other peoples. Only the daily prayer and other forms of worship, such as alms-giving (zakat), inculcate the will to struggle against self-degradation. 
Islam is not racist or ethnocentric. It teaches that all human beings are equal. It removes the barriers of nationalism, color, caste or language. It is against all discriminations and prejudices. It teaches justice for all people. It teaches peace and tolerance, freedom of opinion and expression. Islam establishes a worldwide community of faith and brotherhood.
Islam is a word derived from the root words Silm and Salamah. It means surrendering, guiding to peace and contentment, and establishing security and accord.
Islam is a religion of security, safety, and peace. These principles permeate the lives of Muslims. When Muslims stand to pray, they cut their connection with this world, turning to their Lord in faith and obedience, and standing at attention in His presence. Completing the prayer, as if they were returning back to life, they greet those on their right and left by wishing peace: "Remain safe and in peace." With a wish for safety and security, peace and contentment, they return to the ordinary world once again.
Greeting and wishing safety and security for others is considered one of the most beneficial acts in Islam. When asked which act in Islam is the most beneficial, the Prophet (PBUH) replied, "Feeding others and greeting those you know and those you do not know."
How unfortunate it is that Islam, which is based on this understanding and spirit, is shown by some circles to be synonymous with terrorism. This is a grave historical mistake; wrapping a system based on safety and trust in a veil of terrorism just shows that the spirit of Islam remains unknown. If one were to seek the true face of Islam in its own sources, history, and true representatives, then one would discover that it contains no harshness, cruelty, or fanaticism. It is a religion of forgiveness, pardon, and tolerance, as such saints and princes of love and tolerance as Rumi, Yunus Emre, Ahmed Yesevi, Bediüzzaman  and many others have so beautifully expressed. They spent their lives preaching tolerance, and each became a legend in his own time as an embodiment of love and tolerance.
Jihad can be a matter of self-defense or of removing obstacles between God and human free choice. Our history is full of examples that show how this principle has been implemented in life.
Of course there are and should be occasions where war is unavoidable. However, the Qur'anic verses on jihad that were revealed for particular conditions have been generalized by some short-sighted individuals. Whereas in actual fact war is a matter of secondary importance, it has been given priority as an essential issue by these people. Such people do not understand the true meaning and spirit of Islam. Their failure to establish a proper balance between what is primary and what is secondary leads others to conclude that Islam advocates malice and hatred in the soul, whereas true Muslims are full of love and affection for all creation.
God created the universe as a manifestation of His love for His creatures, in particular humanity, and Islam became the fabric woven out of this love. In the words of Bediüzzaman  , love is the essence of creation. Just as a mother's love and compassion compels her to allow a surgeon to operate on her sick child to save his or her life, jihad allows war, if needed, to preserve such fundamental human rights as the right to life and religious freedom. Jihad does not exclusively mean war.
While the Prophet of Mercy was inordinately sensitive when it came to respecting others, some Muslims today justify unpleasant behavior on the basis of religion. This shows that they do not understand Islam, a religion in which there is no place for malice and hatred.
The Qur'an strongly urges forgiveness and tolerance. In one verse, it says of pious people:
They swallow their anger and forgive people. God loves those who do good. 
Another verse, while mentioning the characteristics of believers, says:
When they meet hollow words or unseemly behavior, they pass them by with dignity. 
Success Here and Hereafter:
Islam wants its followers to be happy and successful in this world. Islam is not pessimistic, morbid or ascetic. Allah Almighty says: (Say: Who hath forbidden the beautiful (gifts) of Allah, which He hath produced for His servants, and the things, clean and pure, (which He hath provided) for sustenance? Say: They are, in the life of this world, for those who believe, (and) purely for them on the Day of Judgment. Thus do We explain the Signs in detail for those who understand. Say: The things that my Lord hath indeed forbidden are: shameful deeds, whether open or secret; sins and trespasses against truth or reason; assigning of partners to Allah, for which He hath given no authority; and saying things about Allah of which ye have no knowledge) 
And Allah says about the Salvation in the Hereafter:
(Say: O my Servants who have transgressed against their souls! despair not of the Mercy of Allah: for Allah forgives all sins: for He is Oft-Forgiving, Most Merciful) 
He Almighty also says: (So set thy purpose (O Muhammad) for religion as a man by nature upright the nature (framed) of Allah, in which He hath created man. There is no altering (the laws of) Allah's creation. That is the right religion, but most men know not) 
Life is the foremost manifest blessing of God Almighty, and the true and everlasting life is that of the Hereafter. Since we can deserve this life only by pleasing God, He sent Prophets and revealed Scriptures out of His out-pouring mercy for humanity. While mentioning His blessings upon humanity, He begins: All-Merciful. He taught the Qur'an, created humanity, and taught it speech. 
All aspects of this life are a rehearsal for the afterlife, and every creature is engaged toward this end. Order is evident in every effort, and compassion resides in every achievement. Some "natural" events or social convulsions may seem disagreeable at first, but we should not regard them as being incompatible with compassion. They are like dark clouds or lightning and thunder that, although frightening, nevertheless bring us the good tidings of rain. Thus the whole universe praises the All-Compassionate.
Islam opposes all the oppressors of history in the world, it upholds man's whole-hearted surrender to the Lord of the universe. It must be clearly understood that Islam does not oppose any human values, or human rights; and what it objects to is the negation of God to emphasize the authority of Man in the universe, which is the underlying philosophy of secular humanism; and this Islam rejects.