Younus ibn Yaqub, one of the great followers of Imam Ja'far al-Sadiq (a) quotes: That very year during the Hajj season we, the followers of the Imam (a) were in his presence as usual. Hamran ibn A'yan, Muhammad ibn No'man, Hisham ibn Salem, Hamzah ibn Taiyar, Momen Tagh and a few others were present. At that time Hisham ibn Hakam entered our gathering and approached the Imam (a). Although, he was still very young, Imam Ja'far ibn Muhammad (a) paid more respect to him than to any of the others present there and seated him nearer to himself than any of the other followers. However, as the Imam (a) felt that this show of respect towards him was not pleasing to others, said: "This young man (pointing at Hisham) wholeheartedly helps us with all his power, strength and arguments."
Then he said: "O Hisham, would you not tell us what happened between you and Amr ibn Obeid? And would you not disclose what you did with him and what calamity you brought upon him? Tell me the details of the story and questions you put to him and repeat everything for us."
Hisham said respectfully: "O the son of the Prophet of God, I consider your good self so much exalted and know so much about your great personality that I feel ashamed of saying something in your presence. Also my tongue has no power to say anything before you."
The Imam said: "However, we desire this of you. So you must obey and do as we say."
Now under these circumstances, Hisham decided to retell his journey to Basrah and his debate with Amr ibn Obeid and began his story like this: "I became informed that Amr ibn Obeid1 used to sit in the Mosque of Basrah amidst the gathering of his disciples, and discuss about Imamate and Wilayah (trusteeship) and reject our Shi'a beliefs and the followers of the Prophet's household (Ahlul Bayt). This news made me unhappy and I began my journey to Basrah. As I reached Basrah on Friday, I went directly to the Mosque of Basrah. All of a sudden my eyes fell upon the huge crowd of people who encircled Amr. He had put on a black coloured silken garment which had decorated bordering and also had put on his shoulders something like a robe. People were trying to listen to him from all nooks and crannies by stretching their heads. They were posing questions and he was replying to them. I managed to find a place for myself in a corner and sat on both my knees with some trouble. Then I turned my face to Amr ibn Obeid and said: "O learned man, I have just come now and I am a stranger. Do you allow me to ask you some questions?" He allowed me. Then I began my questions as follows:
Do you have eyes?
My son, what sort of a question is this which you ask of me!
There is no need to ask some thing which you are seeing yourself!
All my questions are like this.
Ask my son, however much your questions may be foolish.
I would ask provided you reply to my all questions whatever they might be.
Very well, ask!
Do you have eyes?
What do you do with your eyes?
I see colours and figures.
Do you have a nose?
What do you do with your nose?
Do you have a mouth?
What do you do with your mouth?
I partake of the victuals and beverages.
Do you have a tongue also?
Yes, I do.
What do you do with it?
I speak with the help of my tongue.
Do you have ears?
What do you do with your ears?
I listen to sounds.
What about hands? Do you have hands too?
Yes, I do.
What is the use of your hands?
I accomplish heavy works with their help. I feel the softness and hardness of a thing by touching with them.
Do you have legs also?
Yes I do.
What benefit do they give you?
I go from one place to another by the help of them.
All right, tell me do you have a heart?
Yes, I do.
When you have all the apparent parts of your body, then what do you do with your heart?
With the help of my heart, I judge their acts and their effects upon my body and senses.
Is it not possible that these parts of your body were not in need of a heart as all parts of your body were already in good condition?
No, how it is possible that a human being be without a heart?
A human being who is well and all parts of his body function properly, is no longer in need of a heart.
O son, what happens if these parts of the body may be misled in doing their duties or their actions maybe doubtful. For example; if the sense of smelling may not be clear regarding what it has smelled; or the eye regarding whatever it has seen; likewise the sense of taste regarding whatever it has tasted or the ear regarding whatever it has heard; and likewise the sense of touch regarding whatever it has touched. Then they consult with the heart and the heart which is like the capital of a country, checks and judges and puts that doubt aside.
(Hisham says: when the discussion reached this point, I said to Amr):
Therefore, the necessity of the heart for maintaining and managing the realm of the human body is a must. So, God had created the heart of the human being to manage the affairs of the realm of the human body, otherwise the parts of the body would not discharge their duties correctly and would have committed mistakes. Isn't that so?
I said: "O, Aba Marwan,2 how is this possible? The Almighty Creator who has not left your body without any guide, to adjust their actions and help them to perform their duties correctly, has put a leader namely the heart, in the body. He has done that so that they may not be bewildered and every one of them may understand its own duty. Do you think He has left His servants free to be bewildered and live in dispute and discord without appointing any leader enabling them to solve their problems and free themselves from doubt and confusion?"
(Hisham says): Amr ibn Obeid became silent after hearing these words and fell into deep thought. He turned to me after a few moments and asked: Are you Hisham! Hisham ibn Hakam!?
Are you one of his friends and comrades?
Where are you from then?
An inhabitant of Kufa.
Then certainly you are that very Hisham! Then he stood up, embraced me and seated me near himself. While we were sitting there, he was in deep thought as before and did not say anything.
Younus ibn Yaqub says: "When Hisham narrated this story, Imam (a) smiled and asked: 'O Hisham, who has taught you this way and style of debate and speech?'"
He replied: "Likewise I just uttered it, and whatever I have learnt, it is from your good self!"
Imam (a) said: "By God, this debate has been written in the same manner in Sohaf Abraham (a) and Sohaf Musa (a)"4 (The Treatise of Abraham and the treatise of Moses).