He was called al-Shayba`ni. He was given the kunya of Abu` al-Hasan. It was said that he was given the kunya of Abu` Hamza. He belonged to the next generation. He was among the companions of Ima`m al-Ba`qir, peace be on him. He was among the main religious scholars, and among the outstanding narrators. He was among those who knew the truth, and among those who declared the religion of Allah. We will mention some of his affairs:

His Scientific Rank.
Hamra`n was among the main religious scholars, who conveyed the message of Islam, and knew it in detail. He learned his sciences from the Ima`ms of the members of the House (ahl al-Bayt), peace be on them. He studied under Ima`m al-Ba`qir, peace be on him. Then he studied under Ima`m al-Sa`diq, peace be on him. He learned many of his sciences. Ima`m al-Sa`diq, peace be on him, supplied proof of his wide knowledge and outstanding merits. The narrators said that a Syrian came to Ima`m al-Sa`diq, peace be on him, to test him. The Ima`m, peace be on him, asked the Syrian: What is your need?"
I have heard that you have knowledge of all questions," replied the Syrian.
The Ima`m smiled at him, and then he said to him:
In what?" asked the Ima`m.
In the Koran," replied the Syrian.
The Ima`m turned to Hamra`n and said to him:
Take the man.
The Syrian became angry and said: "I want to (question) you, not Hamra`n.
The Ima`m smiled at him and said:
If you overcame Hamra`n, then you would overcome me. The Syrian began questioning Hamra`n, who answered all his questions. Then the Ima`m asked the Syrian: "What is your opinion of Hamra`n? He is skillful. He has answered all my questions.
This initiative of Hamra`n shows his wide knowledge and sciences. Abu` Gha`lib al-Razi said: "Hamra`n was among the greatest Shi'ite scholars. He was among those who memorized the Koran by heart. Moreover, he was an excellent grammarian and linguist.

His Rank with the Ima`ms
Hamra`n had an honorable rank with the Ima`ms of guidance, peace be on them. Many traditions were reported on their authority. In the traditions they praised and lauded him. The following are some of these traditions: Bukayr b. A'yun reported he said: "I went to make the pilgrimage (to Mecca) for the first time I arrived at Mina. There I asked (the people) about the tent of Abu` 'Abd Allah (al-Sa`diq). I entered the tent. I found some people in it. I looked at their faces, but did not find him among them. He was on the side in the tent. He was treating himself by cupping. He said: 'Come to me.' Then he said: 'O Young man, are you from the children of A'yun?' I said: 'Yes, may Allah make me ransom for you.'
He said: 'Who are you?' I said: 'I am Bukayr b. A'yun.' He said to me: 'What Hamra`n has done?' I said: 'He will not perform the hajj this year. He is longing for you. He sends you his greetings.' He returned the greetings, and then he said: 'Hamra`n is a believer. He is among the people of the garden. By Allah, he has no doubt about (the Ima`mate).
2. Zayd al-Shahha`m reported. He said: [Abu` 'Abd Allah (al-Sa`diq), peace be on him, said to me:] "No one has put my words into effect, obeyed my orders, and followed my example except two men, may Allah have mercy on them. They are 'Abd Allah b. Abi Ya`foor, and Hamra`n b. A'yun. They are two sincere believers from our Shi'ites. Their names are with us in the book of the people of the right hand (ashab al-yemeen), which Allah gave to Mohammed, may Allah bless him and his family.
3. Abu` Kha`lid al-Akhras reported on the authority of Hamra`n, who said: [I said to Abu` Ja'far (al-Ba`qir), peace be on him:] "May I be your ransom, I have sworn that I will not leave Medina till I know what I am." He , peace be on him, said: "O Hamra`n, what do you want?" I (Hamra`n) said: "I want you to tell me what I am." He, peace be on him, said: "You are our follower (shi'ite) in here and hereafter. Al-Kashi reported another group of traditions that show the high rank of Hamra`n with the Ima`ms of the members of the House (ahl al-Bayt), peace be on them.

His intense Obedience to the Ima`ms.
Hamra`n was very obedient to the Ima`ms. He loved them from the bottom of his heart. The narrators said: "When Hamra`n sat with his companions, he mentioned the outstanding merits of the members of the House (ahl al-Bayt), peace be on them. When his companions wanted to mix the outstanding merits of the members of the House (ahl al-Bayt), peace be on them, with other than them, he left them and went away. Indeed, this is the maximum degree of obedience and love for the Ima`m.

Bibliography:
1. Al-Kashi.
2. Mu'jam Rijal al-Hadith
3. Tanqih al-Maqal
4. Ibn al-Nadim, Fihrist
5. Al-Tusi, Fihrist