Imam al-Sadiq, peace be on him, asked Hisham to tell him about his debates with ‘Amru b. ‘Ubayd, the spiritual leader of the Mu‘tazilites. However, Hisham said to him:
-Surely I magnify you, feel shame of you, so my tongue cannot function before you.
-When I order you (to do) something, then you have to do it.Hisham obeyed the Imam and began telling him about his story with ‘Amru b. ‘Ubayd, saying to him:
-I heard about ‘Amru b. ‘Ubayd and his sitting in Basrah Mesjid. I regarded that as great, for he denied the Imamate and said: “Allah’s Apostle died without (appointing) a testamentary trustee (of authority). So I went out to him. I entered Basrah and went to its Mesjid. I found a great seminar. I saw ‘Amru b. ‘Ubayd wearing a woolen cloak as a loincloth and wearing another cloak as a garment. While the people were questioning him, I asked them to make way for me, and they did. He squatted at the back of the people. Then I asked him:
-O Scholar, I am a stranger! May I ask you a question?
-Yes.
-Do you have eyes?
-O My little son, what a kind of question is this?
-This is my question!
-O My little son, even if your question is foolish?!
-Give me an answer to it.
-Question!
-Do you have eyes?
-Yes.
-What do you see with them?
-I see with them colors and persons.
-Do you have a nose?
-Yes.
-What do you do with it?
-I smell with it.
-Do you have a tongue?
-What do you do with it?
-I speak with it.
-Do you have an ear?
-Yes.
-What do you do with it?
-I hear sounds with it.
-Do you have hands?
-Yes.
-What do you do with them?
-I strike with them, and distinguish the soft from the coarse.
-Do you have legs?
-Yes.
-What do you do with them?
-I move from one place to another with them.
-Do you have a heart?
-Yes.
-What do you do with it?
-With it I perceive all that which comes through these limbs.
-Are these limbs in no need of the heart?
-No.
-How is that, and they are healthy and sound?
-O My little son, surely if the limbs have doubt of a thing, they smell it or taste it, so they send it to the heart; accordingly, certitude is sure, and doubt is false.
-Has Allah installed the heart for the doubt of the limbs?
-Yes.
-So there is no escape from the heart; otherwise the limbs are not sure (of things)?
-Yes.
After Hisham had taken these premises from ‘Amru, he repeated to him that his belief in that Allah’s Apostle died without (appointing) a testamentary trustee (of authority) was invalid, saying to him: -O Abu Merwan, surely Allah has not left your limbs without an Imam (leader); He has appointed an Imam to them to confirm the correct and negate that of which they have doubt; therefore, how did He leave all the creatures in perplexity, doubt, and differences? Why did He not appoint an Imam over them, that they might resort to him when they were doubtful and perplexed, while He has appointed an Imam over your limbs, that you may resort to him when you are doubtful and perplexed?
‘Amru kept silent and was unable to give an answer, for Hisham had blocked all the avenues before him. Then he turned to him and asked him:
-Are you Hisham?
-No.
-Did you sit with him?
-No.
-Where are you from?
-From Kufa.
-Therefore, you are he.
Then he shook hand with him, made him sit in his place, and said nothing until he went away. The Imam was very pleased with this wonderful debate. ( Al-Keshi, Rijal, pp. 176-177. Al-Amali, vol. 1, p. 55. Al-Mas’udi, Murujj al-Dhahab, vol. 2, p. 382.)