His first wife was Fatima, the only daughter of Muhammad, during whose lifetime, he did not marry any other lady. By Fatima, he had three sons, Hasan, Hussain and Mohsin, who died in infancy; and two daughters, Zainab and Umm Kulsum. By his wife, Ummul Banin bint Hizam, Ali had four sons, viz. Abbas, Jafar, Abdullah and Uthman. By Layla bint Masud, he had Ubaidullah and Abu Bakr. By Asma bint Umyas, he had Yahya and Muhammad Asghar. By Umm Habiba bint Rabia, he had one son, Umar and a daughter, Ruqaiya. By Amama bint Abil Aas, he had a son, named Muhammad al-Awasat. By Khawla bint Jafar bin Qais al-Hanafiya, he had Muhammad Akbar, who was known as Muhammad ibn Hanafiya. By Umm Sa'id bint Urwa bin Masud, he had Ummul Hasan and Ramla.
It is difficult to design a portrait of the qualities and merits of Ali bin Abu Talib, for he was a paragon of virtues and fount of knowledge. He was indeed a living encyclopaedia of learning. The Sufis traced their esoteric chains back to Ali. Abu Nasr Abdullah Sarraj writes in "Kitab al-Luma fi't-Tasawwuf" (ed. Nicholson, London, 1914, p. 129) that when Junaid Baghdadi (d. 298/910) was asked about Ali's knowledge in esoteric field, he said, "Had Ali been less engaged in wars, he might have contributed greatly to our knowledge of esoteric things for he was one who had been vouchsafed ilm al-ladunni (i.e., spiritual knowledge direct from God)."
Ali taught to his followers that Islam is the only religion which is in harmony with intellect in its objectives and agrees with nature in its commands and prohibitions. The great revolution which Islam brought about in the domain of religion was obviously stimulated by the attitude which it adopted in regard to the supremacy of reason. He called upon the people to accept the sovereignty of intellect, and invited them to reflect and ponder over the natural phenomenon. According to Ali, Islam before everything else is the religion of reason, and not a path of blind faith, and accordingly, it requires its adherents to be wise, able and intelligent, in possessing of penetrating insight; so that they might always act in accord with the dictates of justice and truth, and build sound character. For these, Ali raised the dignity of knowledge (ilm) through his various sermons and speeches. It infers from his teachings that knowledge covers all branches, and it is not confined to the religious knowledge, otherwise, the Arabs would have stopped at the boundaries of theology alone.
Ali is attributed with having been the founder of the study of Arabic grammer through his disciple, Abdul Aswad al-Dulai; and the originator of the correct method of reciting Koran. His works have been collected by Sharif al-Razi Zul Hussain Muhammad bin Hussain bin Musa al-Musawi (d. 408/1015) into a vast compendium, called "Nahjul Balagha" (Course of Eloquence), an anthology of his sermons, letters, discourses, exhortations, advices, judgements on penal, civil and commercial law, proposed solutions of fiscal and economic problems. It represents the best early example of Muslim writing on philosophy, theology, science and ethics. In its sanctity, the work is regarded by the Shiites as second only to the Koran.
While studying his discourses, we will know that many modern scientific theories had been expounded by Ali 1300 years ago. Shaikh Ali bin Ibrahim al-Qummi of 3rd century writes in "Wassaffat" that once in a moon-lit night, Ali said: "The stars that you see in the sky, all of them, contain cities like the cities of our earth, and each city is tied to a perpendicular of light, and the length of the perpendicular is a distance of two hundred and fifty years' journey in the sky." The French scholar Mons. Xion was so impressed upon these words that he was constrained to advance his remarks that, "A person who gave such information a thousand years ago without having recourse to any instrument or material means, cannot be having merely human eye or mind, but must have been endowed with divine knowledge, and with such a religious guide and leader, Islam must be a true heavenly religion, which stands proved by the fact that the successor of its founder possessed super human intelligence and knowledge."
It is related that Ali asked an Egyptian astrologer, called Sarsafil, "Tell me what is the relation of venus to the satellites (tawabi) and fixed stars (jawami)?" Sarsafil could not return answer for he knew only Greek astronomy. The Arabic word for satellites is tawabi means "followers", and truly a satellite is a follower of the planet round which it revolves. Similarly, the word for fixed stars is jawamimeans "gatherers" and truly a sun, or fixed star keeps all the planets revolving round it gathered together. How accurate were the terminologies of Ali?
Once a person asked Ali, "What is the distance between earth and the sun?" Ali said, "Suppose a horse runs day and night without any break from earth to sun, it would take 500 years to reach the sun." While making its calculation, it should be known that the speed of an Arabian horse is normally 22 miles per hour. The horse thus would cross 95,040,000 miles in 500 years, indicating a distance between earth and the sun. It must be remembered that the same distance between the earth and sun was commonly accepted in Europe during Renaissance. The western scientists expounded the same distance during 18th century under another notion, that if a jet plane flies from earth at the speed of 10,000 miles per hour, it would reach the sun in 11 years. This method also indicates the distance of 95,040,000 miles, vide "The Book of Knowledge" (ed. by E.V. McLoughlin, New York, 1910). The modern science however shows that when the earth is closest to the sun in the early January, the distance from earth becomes 91,400,000 miles, and when the earth is farthest in early July, the distance becomes 95,040,000 miles. It is therefore safe to conclude that the person would have asked the above question to Ali most possibly in the month of early July.
Philip K. Hitti writes in "History of the Arabs" (London, 1949, p. 183) that, "Valiant in battle, wise in counsel, eloquent in speech, true to his friends, magnanimous to his foes, Ali became both the paragon of Muslim nobility and chivalry and the Solomon of Arabic tradition, around whose name poems, proverbs, sermonettes and anecdotes innumerable have clustered." William Muir was one of the admirers of Ali, who says in his "The Caliphate, its Rise, and Fall" (London, 1924, p. 288) that, "In the character of Ali, there are many things to commend. Mild and beneficent, he treated Basra, when prostrate at his feet, with a generous forbearance. Towards theocratic fanatics, who wearied his patience by incessant intrigues and insensate rebellion, he showed no vindictiveness." R.A. Nicholson writes in "A Literary History of the Arabs" (Cambridge, 1953, p. 191) that, "He was a gallant warrior, a wise counsellor, a true friend and a generous foe. He excelled in poetry and in eloquence; his verses and sayings are famous throughout the Muhammadan East though few of them can be considered authentic." "As the chief of the family of Hashim" writes Charles Mills in "A History of Muhammadanism" (London, 1817, p. 84), "and as the cousin and son-in-law of him, it is apparently increditable that Ali was not raised to the caliphate immediately on the death of Muhammad. To the advantage of his birth and marriage, was added to the friendship of the Prophet. The son of Abu Talib was one of the first converts to Islam and Muhammad's favourite appellation of him was, the Aaron of a second Moses. His talent as an orator, and his intrepidity as a warrior, commended him to a nation in whose judgement courage was virtue and eloquence was wisdom." According to "History of Arabia and its People" (London, 1852, p. 307) by Dr. Andrew Crichton, "This prince united the qualifications of a poet, an orator, and a soldier, for he was the bravest and most eloquent man in his dominions. A monument of his wisdom still remains in a collection of precepts or sentences of which 169 have been translated by Ockley." Thomas Carlyle writes in "Heroes and Hero-worship" (London, 1850, p. 77) that, "As for this young Ali, one cannot but like him. A noble minded creature, as he shows himself, now and always afterwards; full of affection, of fiery daring. Sometimes chivalrous in him, brave as a lion, yet with a grace, a truth and affection worthy of Christian knighthood."
Despite his engagements in the civil wars during his caliphate, Ali however made many reformations in the state. He was the first to realize land revenue from peasants. He exempted taxes on horse-trade to promote its trade. He included forests as a source of revenue for the first time, and necessary tax was imposed on it. He reserved a specific part in poor-rate for the poors. He codified Islamic laws for the judges, and set up courts in every province. Ali was the first to make metalled roads in the state, and constructed many forts, notably Astkhar fort. He reorganised the army, and erected military posts everywhere. He was the first to build a strong bridge on river Euphrates.
Ali's period is also acclaimed for the promotion of education, and he was the first caliph to patronise education, and as a result, about 2000 students in Kufa got free scholarship.