Ibn Abil Hadid: This well-known Egyptian commentator on the book Nahjal Balagha (The Peak of Eloquence) says that Ali had a personality in which opposing characteristics had so gathered themselves that it was difficult to believe that such a combination could manifest itself in a human being. He was the bravest man and boldest warrior that history could cite, and while such brave persons are usually hard-hearted, cruel, and bloodthirsty, instead Ali was kind, sympathetic, responsive, and a warmhearted person. These are the qualities of a pious and God-fearing person. He was friendly with the rich, poor, educated, and ignorant alike. He had a tender spot in his heart for everyone who was downtrodden, crippled, widowed, and orphaned. He was frequently seen smiling and giving happy greetings to others. He was known to be very witty and could not be overcome in debate.

Allamah Askari Ja’fari: A prominent scholar and translator of the book Nahjul Balagha says: “The world cannot quote an example, other than that of Ali, who was a first-class warrior and marshal, a philosopher and moralist, and a great teacher of religious principles and theology. The study of his life shows that his sword was the only help, which Islam received during its early days of struggle and wars of self-defense. For Islam, he was the first line of defense, the second line of defense, and the last line of defense.”

Thomas Carlyle, Scottish historian, critic, and sociological writer (1795–1881): “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. (There was) something chivalrous in him; brave as a lion; yet with a grace, a truth, and affection worthy of Christian knighthood.”

[On Heroes, Hero-Worship, And the Heroic in History, 1841, Lecture 2: The Hero as Prophet. Mahomet: Islam, May 8, 1840]

Edward Gibbon, considered the greatest British historian of his time (1737–1794): “The zeal and virtue of Ali were never outstripped by any recent proselyte. He united the qualifications of a poet, a soldier, and a saint; his wisdom still breathes in a collection of moral and religious sayings; and every antagonist, in the combats of the tongue or of the sword, was subdued by his eloquence and valour. From the first hour of his mission to the last rites of his funeral, the apostle (Muhammad) was never forsaken by a generous friend, whom, he delighted to name his brother, his vicegerent, and the faithful Aaron of a second Moses.”
[The Decline and Fall of the Roman Empire, London, 1911, volume 5, pages 381–2]

Dr. Henry Stubbe, classicist, polemicist, physician, and philosopher (1632–1676): “He had a contempt of the world, its glory and pomp, he feared God much, gave many alms, was just in all his actions, humble and affable; of an exceeding quick wit and of an ingenuity that was not common, he was exceedingly learned, not in those sciences that terminate in speculations but those which extend to practice.”
[An Account of the Rise and Progress of Mahometanism, 1705, page 83]

Charles Mills, leading historical writer of his time (1788–1826): “As the chief of the family of Hashim and as the cousin and son-in-law of him whom the Arabians respected…to the advantages of his birth and marriage was added the friendship of the Prophet. The son of Abu Talib was one of the first converts to Islamism and Mohammad’s favourite appellation of his was the Aaron of a second Moses. His talents as an orator, and his intrepidity as a warrior, were grateful to a nation in whose judgment courage was virtue and eloquence was wisdom.”
[An History of Muhammedanism, London, 1818, page 89]

Simon Ockley professor of Arabic at the University of Cambridge (1678–1720): “One thing particularly deserving to be noticed is that his mother was delivered of him at Mecca, in the very temple itself; which never happened to anyone else.”
[History of the Saracens, London, 1894, page 331]

Washington Irving well known as the “first American man of letters” (1783–1859): “He was of the noblest branch of the noble race of Koreish. He possessed the three qualities most prized by Arabs: courage, eloquence, and munificence. His intrepid spirit had gained him from the prophet the appellation of The Lion of God, specimens of his eloquence remain in some verses and sayings preserved among the Arabs; and his munificence was manifested in sharing among others, every Friday, what remained in the treasury. Of his magnanimity, we have given repeated instances; his noble scorn of everything false and mean, and the absence in his conduct of everything like selfish intrigue.” [Lives of the Successors of Mahomet, London, 1850, p. 165] “He indulged in the poetic vein himself, and many of his maxims and proverbs are preserved, and have been translated in various languages. His signet bore this inscription: ‘The kingdom belongs to God.’ One of his sayings shows the little value he set upon the transitory glories of this world, ‘Life is but the shadow of a cloud—the dream of a sleeper.’ “
[Lives of the Successors of Mahomet, London, 1850, pages 187-8]

Robert Durey Osborn, major of the Bengal Staff Corps (1835–1889): “With him perished the truest hearted and best Moslem of whom Mohammadan history had preserved the remembrance.”
[Islam Under the Arabs, 1876, page 120]

Allamah Masoodi, well-known historian of Islam: “If the glorious name of being the first Muslim, a comrade of Prophet in exile, his faithful companion in the struggle for the faith, his intimate associate in life, his kinsman, with a true knowledge of his (Prophet’s) teachings, including the book (the Qur’an); if self-abnegation, the practice of justice; if honesty, purity, the love of truth; if knowledge of Law and science, constitute a claim to pre-eminence, then all must regard Ali as the foremost Muslim. We shall search in vain to find, either among his predecessors (except Prophet Muhammad), or among his successors, those virtues that God had endowed him with.”

Dr. Ata Mohy-ud-Din: “Ali was the man of many and varied talents, one of the greatest savants, legislators, generals, statesmen, scholars, and administrators the world has ever known. In his person he combined the knowledge of Adam (the Prophet), the virtue of Noah, the devotion of Abraham, the awe and majesty of Moses, the abstinence and piety of Jesus Christ, the patience and resignation of Job, the wisdom of Solomon, the prowess of Alexander (the great), the iron determination of Julius Caesar, the sagacity and prudence of Plato, the scholastic accomplishment of Cicero and the reformative zeal of Justinian.”
[Ali the Superman, by Dr. Ata Mohy-ud-Din. Muhammad Ashraf Publishers, Lahore, Pakistan 1980]

George Jordac: “Ali formulated such firm rules and presented such solid views for the rights of human beings and the welfare of the human society, that their roots penetrate into the depths of earth and their branches extend up to the heavens.”
[In the book The Voice of Human Justice, by George Jordac, page 83]