Younus ibn Yaqub says: "One day when we were in the presence of Imam al-Sadiq [a], a man from Syria entered and said, "I am a learned man and well-versed in the fields of speculative theology and Muslim jurisprudence and acquainted with religious obligations. I have come to participate in a discussion with your followers and disciples."
The Imam said: "Is your knowledge and reasoning based on the sayings of the Prophet of Islam [s] or on your own way of thinking?"
The Syrian said: "Partly it is based on my own thoughts and partly on the sayings of the Prophet [s]."
Imam said: "Then, do you count yourself as a partner in the prophethood?"
He replied: "No, it is not this way."
Imam asked. "Is obedience to you necessary as is obedience to the Prophet [s]?"
He said: "No."
Younus ibn Yaqub noted that the Imam turned his face towards him and said: "This man, prior to participating in discussion with us, was in conflict with himself and he expressed himself quite contrary to his own claim."
Again the Imam said to him: "O! Younus, you can prove yourself well against him, enter into a discussion with him!"
Younus says that he apologized and said: "O my lord, but you yourself commanded us not to participate in the discussions on theology. And you used to say: "Oh theologians! (i.e. those theologians who do not follow their arguments according to the teachings of Islam, the Prophet [s] and the Imams [a]). Don't enter into a discussion, especially one about which you have no knowledge."
Imam said: "Yes, we rebuked them but this rebuke was for those who discuss according to their own desires, and do not obey us i.e. the pillars of truth."
Then the Imam said to me, "Go outside and whomsoever you see from among the theologians, bring them to me!"
I went out and happened to see "Hamran ibn A'yan" who was well-versed in discussion and argumentation. I brought him to the Imam. Then I brought Hesham ibn Salem and at last Ghais ibn Maser. According to my opinion, Ghais was the most learned man in the field of speculative theology and had learnt the art of oratory and debate from Imam Ali ibn al-Husayn [a].
It was a few days before the Hajj season. The tent of the Imam was pitched near the Masjid-al-Haram (the sacred Ka'aba Mosque), at the foot of the mountain. The Imam, while leaning on the post of the tent, was looking around. Suddenly a camel rider appeared in the distance and was moving rapidly towards us. The Imam said "I swear to the Lord of the Ka'aba, he is Hesham."
At first we thought that he was one of the children of Aqil, namely Hesham whom Imam al-Sadiq [a] loved very much. When he came nearer, we realized that he was Hesham ibn Hakam who was still very young and there was no one younger than him in that group. The Imam [a] greeted and honoured him. Then he said, "Praise to him who defends us wholeheartedly with all his power and means."
(Younus ibn Yaqub says): "At first, the Imam turned his face to Hamran and said: "Enter into a discussion with this Syrian." Hamran started the discussion but could not defeat him. Then the Imam commanded Hesham ibn Salem to debate. Hesham's discussion with that man did not end up with any positive result. The Imam then asked Ghais ibn Maser to take his turn at discussing. While Ghais was busy discussing with that Syrian, the Imam [a] briefly smiled in a pleasing way as he noticed that the Syrian was very nervous and was not a match for Ghais.
Finally, the Imam turned his face to the Syrian and said: "If you like you could also discuss with this young man - Hesham. He accepted but turned rudely towards Hesham and addressed him, "O boy! If you have anything to say about the Imamate of your Imam, tell me?" Hesham, who was very angry and shivering due to his wrath said, "O sir, has your Lord created the human beings in vain and left them without any leader and guide? Or has He paid His kind attention towards them and not left them without any Hujjat or spiritual guide, so that they would not be bewildered?"
The Syrian learned man replied: "Of course, the Kind Creator is generous towards His servants and is not neglectful of them." Hesham said, "If it is just as you say, then describe the conditions of their leadership and guidance." The Syrian replied, "God has appointed His Hujjat (Guide) for the human beings, so that they might not dispute among themselves and not separate from each other. Rather they must love each other and come to friendly terms between themselves. The guide must explain the commandments of the Creator for them."
Hesham asked: "Who is that guide and leader?"
The Syrian replied: "The Prophet [s] of God."
Hesham said: "When the Prophet [s] left this world, who became responsible for the guidance of these people?"
The Syrian replied: "The Qur'an and the traditions of the Prophet."
Hesham said: "Today, it is a very long time since the death of the
Prophet [s]. Do you think the Book and the traditions alone can solve the disputes?"
He replied: "Yes, of course, they are enough and sufficient."
Hesham said: "If it is just as you say, then why do you and I dispute and why have you travelled such a long way from Syria?"
Younus ibn Yaqub says, "When their discussion came to this point, the learned Syrian put his head down and became quiet."
The Imam [a] asked him, "Why don't you speak?"
He said: "What shall I say? I have no reply. Because if I say we have no dispute, then I would be telling a lie. On the other hand, if I say: The Qur'an and the traditions of the Prophet [s] are enough for the solution of the problems, this would also be a false statement. This is due to the fact that it is not easy to understand the meaning of the Qur'an and the traditions. If we dispute and each of us is of the opinion that our own belief is right, then in this case what is the use of the Qur'an and the traditions of the Prophet [s]? This discussion is not to my benefit."
Imam al-Sadiq [a] said: "Ask Hesham himself the solution to your difficult problem."
The learned Syrian turned his face towards Hesham and said:
"O Hesham, tell me yourself who is the supervisor of the deeds of the people and who is their leader? Tell me whether the Creator guides them Himself or the people are themselves responsible for their own leadership?"
Hesham replied: "Neither one of these is correct, rather the Kind Creator has appointed leaders for the people from amongst themselves. The Syrian said: "Whom has He appointed to invite the people to unity and friendship and separate the straight path from that of the wrong one, and the just from that of the unjust?"
Hesham said: "Do you mean in the time of the Holy Prophet [s] or the present time?"
The Syrian said: "The Prophet [s] during his own life was the guide of the people. What I am talking about is the present time."
Hesham, with an ocean of respect and honour, pointed towards the Imam [a] and said: "Today, the only guide for the people is this exalted and holy person in whose presence we are standing now. And the learned men come from all over the world to him to amass knowledge and virtue. It is he who with the help of immense knowledge derived from his ancestors as a heritage, makes us aware of the heavens and the earth."
The Syrian said: "How can I believe this to be so?"
Hesham replied quickly: "Ask the Imam about the future incidents of your life and the accounts of your journey."
The Syrian said: "If it is so then there will be no problem for me."
Then the 6th Imam [a] started to retell one by one, all the happenings and the details of his journey from Syria to Mecca.
The Syrian who was carefully listening to the detailed accounts given by the Imam [a] said to the Imam [a] at the end of the speech: "Whatever have you said is correct, and now I also have become a Muslim."
The Imam [a] said: "Say I have confessed to the faith. Before you were also Muslim but you followed only the mere and apparent rules and regulations of Islam regarding marriage and inheritance etc. It is now necessary to acquaint yourself with our holy family, as the reward and remuneration of God and the recompense in the other world is obtained only by following us and by accepting our leadership. And until this moment you were deprived of this blessing."
As the Syrian accepted the Imam's [a] speech and instructions he said: "I witness that only God is to be worshipped and Prophet Muhammad [s] is the Prophet sent by God. Verily you are the guardian of the Prophet [s] and his other rightful descendants."
 Yunus ibn Yaqub, is one of the famous Hadith narrators and also one of the followers of three of the Imams: Imam Ja'far Al-Sadiq [a] Imam al-Kadhem [a] and Imam Ridha [a]. Najjashi praises him and writes: He has the power of attorney from Imam Mousa b. Ja' far [a]. It is said that he is one of the thiqah (trustworthy) in Kitab Rejal Kashi and there has been a lot written about his virtues. Yunus died in the time of Imam Reza [a]. May God be pleased with him.
 Homam 6. Ayan Shaibani is one of the followers of Imam al-Baqir [a] and Imam al-Sadiq [a]. Shaikh has quoted that he was responsible for some of the affairs on behalf of the 6th Imam [a] and Kashi in his book Rejal, after quoting some virtues in favour of him, writes that Imam Al-Sadiq, [a] has said: Homam b. Ayan is one of the dwellers of Paradise.
 Hesham ibn Salem, is one of the followers of Imam al-Sadiq [a] Najjashi and Allamah have praised him and a few have taken him as one of the Usulioun (Fundamentalists). He was an inhabitant of Jozjan and lived at (in) Kufa.
 Translated and abridged from: Kafi - by Kulaini; (Ehtejaj Bihar al-Anwar) by Majlisi.