After death of Prophet( PBUH), he retired to Basra on the Persian gulf, a stronghold of the ascetic sect. Here he lived undisturbed, though his open disavowal of the reigning family of Ommeyah exposed him to some danger.
The following incident, illustrating his independence of character is narrated by Ibn Khalliqan. When Omar ibn Hubaira was appointed to the government of Irak in the reign of the Caliph Abd-al Malik (a.d. 721) he called for Hasan Basri, Muhammad Ibn Sirin and as Shabi to whom he said, "Abd al Malik has received my promise that I will hear and obey him; and he has now appointed me to what you see, and I receive from him written orders. Must I obey him in whatever orders he takes upon himself to give?" To this Ibn Sirin and as Shabi gave a cautious reply, but Hasan Basri, being asked his opinion, made this answer: "O Ibn Hubaira! God outweighs Abd al Malik, and Abd al Malik cannot outweigh God; God can defend thee from Abd al Malik, and Abd al Malik cannot defend thee from God. He will soon send an angel to take thee from thy throne, and send thee from the width of thy palace into the narrowness of the tomb. Then thy deeds alone can save thee." Ibn Hubaira then rewarded them, but bestowed a double reward on Hasan Basri, upon which as Shabi said to Ibn Sirin, "We gave him a poor answer, and he gave us a poor reward."
Hasan Basri's adoption of the ascetic life was brought about in the following way. When a young man he was a lapidary, and had gone to Roum (Asia Minor) to practise his craft. He there lived on friendly terms with the vizier of that country. One day the vizier said to him, "We are going out of the city to a certain place; will you come with us?" Hasan Basri assented, and went. "We came," he said afterwards, "to a plain where there was a vast tent the ropes of which were of silk and its stakes of gold. I saw a large number of soldiers marching round it; they repeated some words which I could not hear, and then retired. Then came about four hundred mullahs and learned men, who did the same. These were followed by a similar number of old men. Then about four or five hundred beautiful maidens, each holding in her hand a dish containing rubies, pearls, turquoises, and other precious stones. They went in procession round the tent in the same way. Finally the sultan and the vizier went into the tent and came out again.
"As for me, I remained transfixed with astonishment. 'What does all this mean?' I asked the vizier. 'The King,' he said, 'had an extremely beautiful child of a happy disposition, who fell ill and died. His tomb is within this tent, and they visit it once a year. First come the soldiers, who circle round the tent and say, 'O son of the sultan, if we could have ransomed thy life by the strokes of our swords, we would have done it, even had it cost us our own; but God willed otherwise, and we cannot change his decree.' Having so said, they go away. Then the mullahs and learned men, coming in their turn, say, 'O son of the sultan, if we could have ransomed thee by knowledge or by eloquence, we would have done so; but all the knowledge and eloquence in the world cannot arrest the decrees of Allah.' Then they depart. After them come the old men, who cry, 'If we could have saved thee by groanings and prayers, we would have done so; but our intercession is useless.' Finally come the young maidens, who say, 'O son of the sultan, if we could have ransomed thee at the price of beauty and wealth, we would have done it; but the steps of fate turn aside for neither.' After them the sultan and the vizier enter the tent. The sultan says, 'O my son, I have done all that I could do. I have brought all these soldiers, these mullahs, these learned men, these old men, these beautiful maidens bearing treasures, and yet I cannot bring thee back. It depends not on me, but on Him before Whom all power is powerless. May the mercy of the Lord be multiplied upon thee for another year.' Having thus spoken, they return by the way they came.'"
Hasan Basri, having heard this, felt stirred to the depths of his heart. Leaving Roum, he retired to Basra, where he took an oath that he would not smile again till he knew what his eternal destiny would be. He practised the severest asceticism, and many came to hear him preach.
Hasan Basri had a disciple who was in the habit of casting himself on the ground and uttering groans when he heard the Koran recited. "If thou art able to restrain these groans," said he, "they will prove like a destructive fire to thee; but if they are really beyond thy power to control, I declare that I am six stages behind thee in the way of piety. Such groanings," he added, "are generally the work of Satan."
One day Hasan Basri was preaching when Hejaj ben Yusuf, the bloodthirsty and formidable governor of Irak, accompanied by a great number of his retinue with drawn swords, entered the mosque. A person of distinction in the audience said, "We must watch to-day whether Hasan will be embarrassed by the presence of Hejaj." When the latter had taken his place, Hasan Basri, without paying the least attention to him, so far from shortening his discourse, prolonged it. When it was finished, the person who was watching him exclaimed, "Bravo, Hasan!" When he came down from the pulpit, Hejaj came forward, and, taking him by the hand, said, addressing the people, "If you wish to see him whom the Lord has distinguished among you, come and look on Hasan Basri."
Hasan had in his heart such a fear of the Lord that, like a man seated near an executioner, he was always in a state of apprehension. Seeing one day a man who wept, he asked him what was the matter. "To-day," answered the man, "I heard a preacher say that there were a great many among the Moslems who, by reason of their sins would remain several years in hell, and then be taken out." "May God grant," cried Hasan, "that I be one of those who come out of hell at last; may I be even as that man, who, as the prophet of God said, will come out eighty-four years after all the rest."
One night he was overheard weeping and groaning in his house. "Why these tears and laments?" he was asked. "I weep," he answered, "thinking that perhaps to-day I have set my foot in an unlawful place, or allowed an evil word to escape my lips which will cause me to be chased from before the throne of the most high. 'Away!' it will be said to me; 'thou hast no access here, thy works of piety are not accepted.' And what answer shall I make? Behold the reason of my fear." One of his sayings was, "I never saw a certainty of which there is no doubt bear a greater resemblance to a doubtful thing of which there is no certainty than death does."
Hasan Basri had a neighbour named Shamaun, who was an infidel and a fire-worshipper. He fell ill, and his last hour approached. Some one said to Hasan, "Shamaun is your neighbour, and his last hour is come; why don't you go to see him?" Hasan having come to see him, saw that by reason of his assiduous fire-worship, his hair and beard were quite blackened by smoke. Hoping that he would become a Moslem, he said to him, "Come, Shamaun, fear the punishment which the Lord prepares for thee who hast passed thy life of seventy years in infidelity and fire-worship." "As for me," answered Shamaun, "I see on the part of you Moslems three characteristics which I cannot explain, and which hinder me from becoming a Moslem:—(1) You never cease repeating that the world is perishable and impure, and yet day and night, without interval or repose, you heap up its treasures; (2) You say that death is certain and inevitable, and yet you put the thought of it aside, and practise none of the works which should fit you for another world; (3) You assert your belief that in that world it will be possible to contemplate the face of the Most High, and yet you commit acts which He abhors." "Thou speakest like one of the initiated," said Hasan, "but although the faithful commit sins, none the less they confess the unity and the existence of the Most High, whilst thou hast spent thy life in worshipping the fire. At the day of judgment, if they cast us both into hell, the fire will carry thee away at once, but if the grace of the Lord is accorded to me, it will not be able to scorch one of my eyebrows; this shows that it is only a creature. And, moreover, you have worshipped it for seventy years, and I have never worshipped it."
These words made such an impression on Shamaun that he made a profession of the faith of Islam, dying soon afterwards. On the night of his death, Hasan in a dream saw Shamaun wearing a crown of gold, clothed in raiment of resplendent beauty, and walking in Paradise. "My God," he cried when he awoke, "Thou hast had mercy on him who spent seventy years in infidelity; is it strange that Thou shouldest show mercy to the faithful?"
Hasan was a man of such humility of mind that he considered everyone whom he saw his superior. One day when he was walking along the bank of the river Tigris he saw a negro seated near a woman; before them was a jar and a cup. Each of them in turn poured from the jar into the cup and drank. Seeing this man, Hasan, according to his wont, said to himself, "There is a man better than myself." At the same time he secretly thought, "As regards the observance of the ceremonial law, it is possible that he is not superior to me, for he is sitting near a woman of doubtful character and drinking wine." While he was thus reflecting, there appeared on the river a boat heavily laden, and containing seven persons. Just as it was approaching the shore, it foundered. The negro, casting himself into the water, drew out six persons in succession; then, going to Hasan, he said to him, "Rise, if thou art better than I. I have saved six, for my part; thou save one, for thine." Then he added, "O true believers, this jar contains water, and this woman is my mother. I have wished to tempt Hasan." Then, addressing the latter, he said, "See, thou hast looked with the outer eye only, and hast not been capable of looking with the inner eye." At these words, Hasan, falling at his feet, kissed his hand, and understood that he was one of the Lord's chosen servants. "Sir," he said, "as thou hast drawn these drowning men from the water so save me from the abyss of self-worship." The negro replied, "Go, thou art saved." From that time Hasan considered no one smaller than himself, but everyone his superior.
On one occasion, Hasan Basri said, "I have been startled by the sayings of four persons, (1) a drunkard, (2) a debauchee, (3) a child, (4) a woman." "How was that?" he was asked. "One day," he said, "I saw a drunkard staggering in the midst of the mire. I said to him, 'Try and walk so as not to stumble.' 'O Hasan,' the drunkard replied, 'in spite of all your efforts, do you walk firmly in the way of God? Tell me, yes or no. If I fall in the mire no great harm is done, I can get rid of it by washing; but if you fall into the pit of self-conceit, you will never emerge clean and your eternal welfare will be entirely ruined.' These words pierced me to the heart. (2) Again, as I passed once close to a man of infamous character, I drew my robes close about me lest they should touch him. 'O Hasan,' he said, 'why draw thy robes away from contact with me. Only the Most High knows what will be the end of each.' (3) Another time I saw a child coming towards me holding a lighted torch in his hand. 'Where have you brought this light from?' I asked him. He immediately blew it out, and said to me, 'O Hasan, tell me where it is gone, and I will tell you whence I fetched it.' (4) One day a beautiful woman, with her face unveiled, came to me. She had just been quarrelling with her husband, and no sooner had she met me than she began reporting his words. 'O woman,' I said, 'first cover thy face and then speak.' 'O Hasan,' she answered, 'In my excitement I lost reason, and I did not even know that my face was uncovered. If you had not told me I should have gone thus into the bazaar. But you who with so great zeal cultivate the friendship of the Most High, ought you not to curb your eye, so as not to see whether my face was uncovered or not?' Her words sank deeply into my heart."
One day Hasan said to his friends, "You are like the companions of the prophet, on whom be peace." They felt immensely gratified at this, but he added, "I mean your faces and beards are like theirs, but nothing else in you. If you had seen them, such was their absorption in divine things, you would have thought them mad. Had they seen you, they would not have regarded one of you as a real Moslem. They, in the practice of the faith, were like horsemen mounted on swift steeds, or like the wind, or like the bird which cleaves the air; while we progress like men mounted on donkeys with sores on their backs."
An Arab visiting Hasan Basri asked him for a definition of patience. Hasan answered, "There are two kinds of patience; one kind consists in bearing afflictions and calamities bravely and in abstaining from what the Lord has forbidden, the other kind consists in never lending an ear to the suggestions of Satan." "As for me," said the Arab, "I have never seen anyone more retiring from the world and more patient than thyself." "Alas," answered Hasan, "my renouncement of the world and my patience count as nothing." "Why dost thou say so?" exclaimed the Arab. "Because, if I practise renouncement it is only from dread of hell-fire, and if I keep patient it is only because I hope to enter Paradise. Now that man alone deserves to be taken into account who, without self-regarding motives practises patience for the sake of the Most High, and whose renouncement of the world has not Paradise for its object, but only the desire to please God. Such a way of acting is a manifest sign of sincerity of heart."
Asked on another occasion what his spiritual state was like, Hasan replied, "My state is like that of a man shipwrecked in the sea, who is clinging to a solitary plank."
He never laughed. At the moment of death he smiled once, and called out "What sin? What sin?" Someone saw him after his death in a dream, and asked him, "O Hasan Basri, thou who never wert in the habit of smiling, why, when dying, didst thou say with a smile, 'What sin? What sin?'" Hasan answered, "When I was dying I heard a voice which said, 'O Azrael, hold back his soul a little longer, it has still one sin,' and in my joy I exclaimed, 'What sin?'"
The night of his death another of his friends had a dream, in which he saw the gates of heaven open and heard a voice proclaim, "Hasan Basri has come to his Lord, Who is satisfied with him."