The beginning of existence was an act of mercy and compassion without which the universe would be in chaos. Everything came into existence through compassion, and by compassion it continues to exist in harmony.
Muslim sages say that the universe is the All-Compassionate One's breath. In other words, the universe was created to manifest the Divine Name the All-Compassionate. Its subsistence depends on the same Name. This Name manifests itself first as the All-Provider, so that all living creatures can receive the food or nourishment they need to survive.
Life is God Almighty's foremost and most manifest blessing, and the true and everlasting life is that of the Hereafter. Since we can deserve this life by pleasing God, He sent Prophets and revealed Scriptures out of His compassion for humanity. For this reason, while mentioning His blessings upon humanity in Surat al-Rahman (the All-Merciful), He begins: Al-Rahman. He taught the Qur'an, created humanity, and taught it speech (55:1-4).
All aspects of this life are a rehearsal for the afterlife, and every creature is engaged in action 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 incompatible with compassion. They are like dark clouds or lightning and thunder that, although frightening, nevertheless bring us good tidings of rain. Thus the whole universe praises the All-Compassionate.
Muslim sages consider the universe a "created book" issuing from His Attribute of Will. To write a book that people could not understand would be pointless. Therefore, He created Muhammad to tell people what the universe really means, and to relay His Commandments in the Qur'an through Muhammad so that we can know what is expected of us. Only by following these Commandments can we attain an eternal life of happiness. The Qur'an is the ultimate and most comprehensive Divine Revelation; Islam is the last, perfected, and universal form of Divine Religion; and Prophet Muhammad is the embodiment of Divine Compassion, one sent by God as a mercy for all worlds.
Prophet Muhammad is like a spring of pure water in the heart of a desert, a source of light in an all-enveloping darkness. Whoever appeals to this spring can take as much water as needed to quench their thirst, to become purified of all their sins, and to become illumined with the light of belief. Mercy was like a magic key in his hands, for with it he opened hearts that were so hardened and rusty that no one thought they could be opened. But he did even more: he lit a torch of belief in them.
The Messenger preached Islam, the religion of universal mercy. However, some self-proclaimed humanists say that Islam is "a religion of the sword." This is completely wrong. They make a great deal of noise when animals are killed or when one of their own is harmed, but are silent when Muslims are massacred. Their world is built on personal interest. It should be pointed out that abusing the feeling of compassion is just as harmful—sometimes even more harmful—than having no compassion at all.
Amputating a gangrenous limb is an act of compassion for the whole body. Likewise oxygen and hydrogen, when mixed in the proper ratios, form water, a most vital substance. When this ratio changes, however, each element resumes its original combustible identity.
Similarly, it is quite important to apportion compassion and to identify who deserves it, for "compassion for a wolf sharpens its appetite, and not being content with what it receives, it demands even more." Compassion for wrongdoers makes them more aggressive and encourages them to work against others. In fact, true compassion requires that such people be prevented from doing wrong. When the Messenger told his Companions to help people when they were just and unjust, they asked him to explain this seeming paradox. He replied: "You help such people by preventing them from engaging in injustice." So, compassion requires that those who cause trouble either be deprived of their means for, or prevented from, doing so. Otherwise, they eventually will take control and do as they please.
The Messenger's compassion encompassed every creature. In his role as an invincible commander and able statesman, he knew allowing blood-stained, blood-thirsty people to control others would be the most terrible form of tyranny imaginable. Therefore, out of compassion, he required that lambs should be able to live in security against wolves' attacks. He desired, of course, that everyone be guided. In fact, this was his greatest concern: Yet it may be, if they believe not in this Message, you will consume yourself, following after them, with grief (18:6).
But how should he deal with those who persisted in unbelief and fought him to destroy both him and his Message? He had to fight such people, for universal compassion encompasses every creature. This is why, when he was wounded severely at Uhud, he raised his hands and prayed: "O God, forgive my people, for they don't know." 
The Makkans, his own people, inflicted so much suffering on him that he finally emigrated to Madina. Even after that, the next 5 years were far from peaceful. However, when he conquered Makka without bloodshed in the twenty-first year of his Prophethood, he asked the Makkan unbelievers: "How do you expect me to treat you?" They responded unanimously: "You are a noble one, the son of a noble one." He then told them his decision: "You may leave, for no reproach this day shall be on you. May God forgive you. He is the Most Compassionate of the Compassionate." 
Sultan Mehmed the Conqueror said the same thing to the defeated Byzantines after conquering Istanbul 825 years later. Such is the universal compassion of Islam.
The Messenger displayed the highest degree of compassion toward the believers: There has come to you a Messenger from among yourselves; grievous to him is your suffering; anxious is he over you, full of concern for you, for the believers full of pity, compassionate (9:128). He lowered unto believers his wing of tenderness through mercy (15:88), and was the guardian of believers and nearer to them than their selves (33:6). When one of his Companions died, he asked those at the funeral if the deceased had left any debts. On learning that he had, the Prophet mentioned the above verse and announced that the creditors should come to him for repayment. 
 Ibn Hisham, Sira, 4:55; Ibn Kathir, al-Bidaya, 4:344.
 Muslim, "Fara'iz," 14; Bukhari, "Istiqraz," 11.
His compassion even encompassed the Hypocrites and unbelievers. He knew who the Hypocrites were, but never identified them, for this would have deprived them of the rights of full citizenship they had gained by their outward confession of faith and practice. Since they lived among Muslims, their unbelief in eternal life may have been reduced or changed to doubt, thus diminishing their fear of death and the pain caused by the assertion of eternal non-existence after death.
God did not send a collective destruction upon the unbelievers, although He had eradicated many such people in the past: But God would never chastise them while you were among them; God would never chastise them as they begged forgiveness (8:33). This verse refers to unbelievers of whatever time. God will not destroy peoples altogether as long as those who follow the Messenger are alive. Besides, He has left the door of repentance open until the Last Day. Anyone can accept Islam or ask God's forgiveness, regardless of how sinful they consider themselves to be.
For this reason, a Muslim's enmity toward unbelievers is a form of pity. When 'Umar saw an 80-year-old priest, he sat down and sobbed. When asked why he did so, he replied: "God assigned him so long a life span, but he has not been able to find the true path." 'Umar was a disciple of the Messenger, who said: "I was not sent to call down curses on people, but as a mercy" and
I am Muhammad, and Ahmad (praised one), and Muqaffi (the Last Prophet); I am Hashir (the final Prophet in whose presence the dead will be resurrected); the Prophet of repentance (the Prophet for whom the door of repentance will always remain open), and the Prophet of mercy.
Archangel Gabriel also benefited from the mercy of the Qur'an. Once the Prophet asked Gabriel whether he had any share in the mercy contained in the Qur'an. Gabriel replied that he did, and explained: "I was not certain about my end. However, when the verse: (One) obeyed, and moreover, trustworthy and secured (81:21) was revealed, I felt secure about it." When Ma'iz was punished for fornication, a Companion verbally abused him. The Messenger frowned at him and said: "You have backbitten your friend. His repentance and asking God's pardon for his sin would be enough to forgive all the sinners in the world." 
The Messenger was particularly compassionate toward children. Whenever he saw a child crying, he sat beside him or her and shared his or her feelings. He felt the pain of a mother for her child more than the mother herself. Once he said: "I stand in prayer and wish to prolong it. However, I hear a child cry and shorten the prayer to lessen the mother's anxiety."
He took children in his arms and hugged them. Once when hugging his beloved grandsons Hasan and Hussayn, Aqra ibn Habis told him: "I have 10 children, and have never kissed any of them." The Messenger responded: "One without pity for others is not pitied." According to another version, he said or added: "What can I do for you if God has removed compassion from you?"
Once, he said: "Pity those on Earth so that those in the Heavens will pity you." Once when Sa'd ibn 'Ubada became ill, the Messenger visited him at home and, seeing his faithful Companion in a pitiful state, began to cry. He said: "God does not punish because of tears or grief, but He punishes because of this," and he pointed to his tongue.  When 'Uthman ibn Mad'un died, he wept profusely. During the funeral, a woman remarked: "'Uthman flew like a bird to Paradise." Even in that mournful state, the Prophet did not lose his balance and corrected the woman: "How do you know this? Even I don't know this, and I am a Prophet."
A member of the Banu Muqarrin clan once beat his maidservant. She informed the Messenger, who sent for the master. He said: "You have beaten her without any justifiable right. Free her."  Freeing a slave free was far better for the master than being punished in the Hereafter because of that act. The Messenger always protected and supported widows, orphans, the poor and disabled even before announcing his Prophethood. When he returned home in excitement from Mount Hira after the first Revelation, his wife Khadija told him: "I hope you will be the Prophet of this Umma, for you always tell the truth, fulfill your trust, support your relatives, help the poor and weak, and feed guests." 
His compassion even encompassed animals. We hear from him: "A prostitute was guided to truth by God and ultimately went to Paradise because she gave water to a dog dying of thirst. Another woman was sent to Hell because she left a cat to die of hunger." Once while returning from a military campaign, a few Companions removed some young birds from their nest to stroke them. The mother bird came back and, not finding its babies, began to fly around screeching. When told of this, the Messenger became angry and ordered the birds to be put back in the nest. 
Once he told his Companions that God reproached an earlier Prophet for setting fire to a nest of ants.  While in Mina, some of his Companions attacked a snake in order to kill it. However, it managed to escape. Watching this from afar, the Messenger remarked: "It was saved from your evil, as you were from its evil." Ibn 'Abbas reported that when the Messenger saw a man sharpening his knife directly before the sheep to be slaughtered, he asked: "Do you want to kill it many times?"
'Abd Allah ibn Ja'far narrates: "The Messenger went to a garden in Madina with a few Companions. A very scrawny camel was in a corner. Seeing the Messenger, it began to cry. The Messenger went to it and, after staying beside it for a while, severely warned the owner to feed it properly."
His love and compassion for creatures differed from that of today's self-proclaimed humanists, for he was sincere and balanced in this regard—a Prophet raised by God, the Creator and Sustainer of all beings, for the guidance and happiness humanity and jinn, and the harmony of existence. As such, he lived for others, and was a mercy for all the worlds, a manifestation of Compassion.
 Bukhari, "Jana'iz," 45; Muslim, "Jana'iz," 12.
 Muslim, "Ayman," 31, 33; Ibn Hanbal, 3:447.
 Ibn Sa'd, Tabaqat, 1:195;
 Abu Dawud, "Adab," 164, "Jihad," 112; Ibn Hanbal, 1:404.
 Bukhari, "Jihad," 153; Muslim, "Salam," 147.