It is narrated from ‘Ubaydullah bin ‘Abdullah bin ‘Utbah bin Mas‘ud that Sayyiduna ‘Abdullah bin ‘Abbas (may Allah be pleased with them both) related this to him from Sayyiduna Abu Sufyan bin Harb (may Allah be pleased with him). Sayyiduna Abu Sufyan bin Harb (may Allah be pleased with him) said: (The king of Rome) Heraclius sent a man to call him while he was with a caravan of Quraysh. At that time, they had gone to Syria for trade, and this was the period when the Messenger of Allah (peace and blessings be upon him) had made a temporary truce with the Quraysh and Abu Sufyan. Abu Sufyan and the others reached Heraclius at Ilya (Jerusalem), where Heraclius had summoned his court. Around him were the great men of Rome (scholars, ministers, and nobles). Heraclius called them and his interpreter, then asked:“Who among you is the closest relative of the man who claims to be a prophet?”Abu Sufyan says: I spoke up,“I am the closest relative to him.”(Upon hearing this) Heraclius ordered,“Seat him (Abu Sufyan) close to me and his companions behind him.”Then he said to his interpreter,“Tell them that I will ask Abu Sufyan about this man (Muhammad, peace and blessings be upon him). If he lies to me about anything, then you should expose his lie.”(Abu Sufyan says:) By Allah! If I had not been ashamed that they would call me a liar, I would have certainly lied about him (peace and blessings be upon him). Anyway, the first thing Heraclius asked me was... (For ease, we present the narration in dialogue form):

Heraclius: What is his lineage among you?
Abu Sufyan: He is of noble lineage.
Heraclius: Has anyone among you ever made such a claim before?
Abu Sufyan: No.
Heraclius: Was there any king among his ancestors?
Abu Sufyan: No.
Heraclius: Do the nobles follow him or the weak?
Abu Sufyan: The weak have followed him.
Heraclius: Are his followers increasing or decreasing?
Abu Sufyan: They are increasing.
Heraclius: Has anyone, after embracing his religion, become displeased with it and apostatized?
Abu Sufyan: No.
Heraclius: Did you ever accuse him of lying before his claim to prophethood?
Abu Sufyan: No.
Heraclius: Does he deceive?
Abu Sufyan: No, and now we have a fixed truce with him. I do not know what he will do in it. Other than this, I could not add any (lie) to this conversation.
Heraclius: Have you ever fought him?
Abu Sufyan: Yes.
Heraclius: What was the outcome of your battles with him?
Abu Sufyan: Sometimes his side was victorious, and sometimes ours; sometimes they won, and sometimes we did.
Heraclius: What does he command you?
Abu Sufyan: He says,“Worship Allah alone, associate nothing with Him, and abandon the (polytheistic) ways of your forefathers.”He commands us to pray, speak the truth, be pious, and maintain family ties.

(After hearing all this) Heraclius said to his interpreter: Tell Abu Sufyan,“I asked you about his lineage, and you said he is of noble lineage among you. Prophets are always of noble lineage among their people. I asked you if anyone among you had ever made such a claim before, and you said no. If someone had, I would have thought that this man was imitating what had already been said. I asked you if there was any king among his ancestors, and you said no. If there had been, I would have thought that he was seeking to regain his ancestors’ kingdom. I asked you if you ever accused him of lying before his claim, and you said no. I realized that one who refrains from lying to people would not lie about Allah. I asked you whether the nobles or the weak follow him, and you said the weak. Indeed, they are the followers of the prophets. I asked you whether his followers are increasing or decreasing, and you said they are increasing. This is the nature of faith until it is complete. I asked you if anyone, after embracing his religion, became displeased and apostatized, and you said no. Indeed, this is the quality of faith: when its joy enters the heart, it does not leave. I asked you if he ever broke a covenant, and you said no. Prophets do not break covenants. I asked you what he commands you, and you said he commands you to worship Allah alone, not to associate anything with Him, forbids you from idol worship, and commands you to speak the truth and be pious. If what you say is true, then soon he will own the very place where my two feet are. I knew that a prophet was to come, but I did not know that he would be from among you. If I knew I could reach him, I would endure every hardship to meet him. If I were with him, I would wash his feet.”

Heraclius then called for the letter of the Messenger of Allah (peace and blessings be upon him), which he had sent through Dihyah Kalbi (may Allah be pleased with him) to the governor of Busra, who had forwarded it to Heraclius. He read it, and in it was written: «بِسْمِ اللَّـهِ الرَّحْمَـٰنِ الرَّحِيمِ» “This letter is from the servant and Messenger of Allah, Muhammad (peace and blessings be upon him), to the king of Rome. Peace be upon him who follows guidance. After that, I invite you to Islam. If you accept Islam, you will find safety (in this world and the Hereafter), and Allah will grant you a double reward. But if you turn away, then the sin of your subjects will also be upon you. O People of the Book! Come to a word that is just between us and you: that we worship none but Allah, associate nothing with Him, and none of us take others as lords besides Allah. If they turn away, then say (O Muslims): Bear witness that we are Muslims, submitting to Allah alone.”

Abu Sufyan says: When Heraclius had said what he wanted and finished reading the letter, there was a great commotion around him. Many voices were raised, and we were expelled. Then I said to my companions,“The matter of the son of Abu Kabshah (Muhammad, peace and blessings be upon him) has become very great. (See!) Even the king of the Romans fears him.”From that moment, I was sure that the Messenger of Allah (peace and blessings be upon him) would soon prevail, until Allah made me a Muslim.

(The narrator says:) Ibn Nator, the governor of Ilya and a close companion of Heraclius, and the chief priest of the Christians of Syria, used to say: When Heraclius came to Ilya, one morning he woke up troubled. His courtiers asked,“Today we find you changed. What is the reason?”Ibn Nator says: Heraclius was an astrologer, fully skilled in astrology. He told his companions,“Last night I looked at the stars and saw that the king of those who are circumcised has become dominant over our land. Who, in this era, practices circumcision?”They said,“No one but the Jews circumcise, so do not worry about them. Just send orders to all the cities of your kingdom to kill every Jew there.”While they were discussing this, a man sent by the king of Ghassan was brought to Heraclius. He described the situation of the Messenger of Allah (peace and blessings be upon him). When Heraclius heard all the details, he said,“Go and see if he is circumcised.”They checked and reported that he was circumcised. When Heraclius asked about the Arabs, he was told that they practice circumcision. Then Heraclius said,“This is the king of this nation who has appeared.”Then he wrote a letter to a friend of his in Roman (Greek) language, who was as skilled in astrology as Heraclius. Then Heraclius left for Hims (Emesa). He had not yet left Hims when his friend’s reply arrived, and his opinion about the appearance of the Prophet (peace and blessings be upon him) matched that of Heraclius: that Muhammad (peace and blessings be upon him) is indeed a prophet. After this, Heraclius summoned the great men of Rome to his palace in Hims and ordered the doors to be closed. Then he came out and said,“O people of Rome! Do you want success and guidance? If you desire the survival of your kingdom, then pledge allegiance to this Prophet and become Muslims.”(As soon as they heard this) they rushed to the doors like wild donkeys, but found the doors locked. When Heraclius saw their aversion and despaired of their faith, he said,“Bring them back to me.”(When they returned) he said,“What I said was only to test the firmness of your faith, and I have seen it.”(Upon hearing this) they all prostrated before him and were pleased with him. Thus, this was the end of Heraclius’ matter.