Abu Hanifa was among those who believed in the (doctrine) of compulsion and summoned (the people) to believe in it. This belief maintains that the act that issues from man is not created by him and does not issue from him through his choice. Rather it is created by Allah and issues through Allah's will, and that man's will and power has no relationship in finding any deed whether it issues from him through his choice or he is forced to perform it. The Shi'ites have unanimously agreed that such a belief is invalid and incorrect. Besides the jurists have established that it is false; they have conscientiously decided that any optional act should be preceded by some voluntary prerequisites which are as follows:
1. One must imagine the thing in mind.
2. His soul must incline to it.
3. He should perfectly be sure of its advantage.
When these prerequisites are perfect in the horizon of soul, the will clings to deed, and man strives to find it or orders it to be performed, whether it is good or ugly, and there is no coercion or compulsion on man to perform it.
Any way, Abu Hanifa was on top of those who believed in compulsion; he traveled to Yethrib (Medina) to debate with Imam al-Sadiq, peace be on him, on this belief, while he was famous for his being the opponent of it. When he arrived in it, he headed for the Imam's house. He sat in the corridor waiting for a permission to enter. While he was sitting there, a boy came out walking slowly. He asked the boy: "Where does the stranger relieve nature?"
The boy turned to him and said to him: "Slowly!" Then he sat down politely, leaned against the wall, and began to give him an answer to his question, saying: "Avoid the banks of rivers, the places where fruit fall, the courtyards of mosques, and the middle of a road. Hide yourself behind a wall; you should not face the qibla (direction to the Kaaba) nor have your back towards it; and relieve nature where you wish." He explained to him the places where it is detested or forbidden to relieve nature, so Abu Hanifa was dazzled and astonished because he had not thought that there was a boy who had such a scientific ability.
"What is your name?" asked Abu Hanifa.
"Musa b. Ja'far b. Muhammed b. 'Ali b. al-Husayn b. 'Ali b. Abi Talib," was theanswer.
When Abu Hanifa came to know that the boy was a branch of the Tree of the Prophecy and the Imamate, he became tranquil, and then he asked him about the question he had prepared for Imam al-Sadiq, saying: " Boy, from whom does disobedience (issue)? Does it issue from Allah or from the servant?"
The Imam answered him, saying: "Either it issues from Allah and not from the servant at all, so Allah does not punish the servant for what he does not do; or it issues from the servant and Allah, and Allah is a stronger partner. Therefore, the stronger partner has no right to punish the weak for a sin in which they are equal; or it issues form the servant and not from Allah. So If He wills to pardon (him), (He will pardon him), and If He wills to punish (him), (He will punish him); and Allah is He whose help is sought." According to the rational restriction, this conclusion is full of all the elements of the firm scientific proofs man cannot invalidate or refute.
Abu Hanifa became dazzled and astonished, so he raised his voice, saying: "I am satisfied with what I have heard!"
He went out defeated; inability appeared on his face. He did not met with Imam al-Sadiq; the Imam's answer to him and his inability to replay him became famous among the scientific circles; accordingly, a poet composed a poem on the answer of the Imam, peace be on him, to Abu Hanifa, saying:
Our deeds through which we are dispraised have three meanings when we perform them: either our Lord create them by Himself, so we are not blameworthy when we perform them,
Or He shares them with us, so the sin that befalls us will befall Him,
Or my Lord has no sin in performing them, so the sin belongs to him who performs them.
This attitude indicates that Imam Musa had abundant sciences and knowledge during his early age. For he understood what the intellects of the great religious scholars did not understand. For example, Abu Hanifa was unable to stand before his flowing thinking. He found no way to safe and preserve his position except withdrawing from him and avoiding discussing with him any subject matter; this attitude shows that the Imam had abundant knowledge and cleverness none had in such an age except his forefathers, who were singled out with the Imamate.