Abdullah bin Abbas reported,

The Messenger of Allah ﷺ wrote to Caesar inviting him to Islam, sending his letter with Dihya Kalbi. The Messenger of Allah ﷺ instructed him to deliver it to the governor of Bosra, who would in turn pass it on to Caesar. So the governor of Bosra delivered it.When Allah had repelled the Persian armies from Caesar, he walked from Homs to Aelia in gratitude, with carpets spread out for him along the way.Abdullah bin Abbas said, "When Caesar received the letter of the Messenger of Allah ﷺ, he said upon reading it, 'Find me someone from his people whom I may question about the Messenger of Allah ﷺ.'"Ibn Abbas said, Abu Sufyan bin Harb informed me that he was in Sham at the time, among some men of Quraysh who had come there as traders. This was during the truce between the Messenger of Allah ﷺ and the disbelievers of Quraysh.Abu Sufyan said, "Caesar's messenger came to me and took me and my companions until we arrived at Aelia. We were brought before him while he was seated in his royal court wearing his crown, with the great men of Rome around him. He said to his interpreter, 'Ask them which of them is the closest in kinship to this man who claims to be a prophet.'"Abu Sufyan said, "I am the closest of them to him in kinship."Caesar asked, "What is your relation to him?"I said, "He is my cousin."Abu Sufyan continued, "There was no one in the caravan that day from Banu Abd Manaf besides me. Caesar said, 'Bring him close to me.' Then he ordered my companions to be placed behind my back, near my shoulders. He then said to his interpreter, 'Tell his companions that I am going to question this man about the man who claims to be a prophet. If he lies, contradict him.'"Abu Sufyan said, "By Allah, were it not for the shame of my companions reporting that I had lied, I would have lied about him when he questioned me. But I was ashamed that they would report a lie from me, so I told the truth about him."Caesar then said to his interpreter, "Ask him, what is the lineage of this man among you?"I said, "He is of noble lineage among us."He asked, "Has anyone among you ever said this kind of thing before him?"I said, "No."He asked, "Did you ever accuse him of lying before he said what he said?"I said, "No."He asked, "Was any of his forefathers a king?"I said, "No."He asked, "Is it the noble of the people who follow him, or the weak among them?"I said, "Rather, the weak among them."He asked, "Are they increasing or decreasing?"I said, "Rather, they are increasing."He asked, "Does anyone abandon his religion out of displeasure with it after entering into it?"I said, "No."He asked, "Does he ever break his promises?"I said, "No, but we are now in a truce with him and we fear he might."Abu Sufyan said, "No other statement allowed me to slip in something to disparage him besides this one, and even then I feared a lie would be reported from me."Caesar asked, "Have you fought him, or has he fought you?"I said, "Yes."He asked, "How has the war between you gone?"I said, "It has gone back and forth, sometimes the victory is ours and sometimes his."He asked, "What does he command you to do?"I said, "He commands us to worship Allah alone and associate nothing with Him, and he forbids us from what our forefathers used to worship. He commands us with prayer, truthfulness, chastity, fulfilling promises, and rendering trusts."When I had said this, Caesar said to his interpreter, "Tell him, I asked you about his lineage among you, and you claimed that he is of noble lineage. Likewise, messengers are sent within the noble lineage of their people. I asked you whether anyone among you had ever said such a thing before him, and you claimed no one had. Had someone said it before him, I would have said this is a man following a statement made before him. I asked you whether you had accused him of lying before he said what he said, and you claimed you had not. So I knew that one who would not lie about people would not lie about Allah . I asked you whether any of his forefathers was a king, and you claimed not. Had any of his forefathers been a king, I would have said this is a man seeking the kingdom of his ancestors. I asked you whether the nobles of the people follow him or the weak, and you claimed the weak follow him, and they are indeed the followers of messengers. I asked you whether they are increasing or decreasing, and you claimed they are increasing, and so does faith until it is complete. I asked you whether anyone abandons his religion out of displeasure after entering into it, and you claimed not, and likewise faith, when its delight mingles with the hearts, no one becomes displeased with it. I asked you whether he breaks his promises, and you claimed not, and likewise are the messengers. I asked you whether you fought him and he fought you, and you claimed yes, and that your war has gone back and forth, sometimes against you and sometimes for you. Likewise, the messengers are tested, but the final outcome is theirs. I asked you what he commands you with, and you claimed he commands you to worship Allah alone, associating nothing with Him, and he forbids you from what your forefathers worshipped, and he commands you with truthfulness, prayer, chastity, fulfilling promises, and rendering trusts. This is the description of a prophet. I knew he was about to emerge, but I did not think he would be from among you. If what you have said is true, he will soon possess the ground beneath these two feet of mine. By Allah, if I thought I could reach him, I would have made every effort to meet him, and were I in his presence, I would wash his feet."Abu Sufyan said, "Then he called for the letter of the Messenger of Allah ﷺ and ordered it to be read. It said, 'In the name of Allah, the Most Compassionate, the Most Merciful. From Muhammad, the servant and Messenger of Allah, to Heraclius, the great one of Rome. Peace be upon whoever follows the guidance. To proceed, I invite you with the call of Islam. Embrace Islam and you will be safe, embrace Islam and Allah will give you your reward twice over. But if you turn away, then upon you is the sin of the Arisiyyin (meaning the peasants). And, "People of the Book, come to a word that is fair between us and you, that we worship none but Allah, that we associate nothing with Him, and that none of us takes others as lords beside Allah. But if they turn away, then say, 'Bear witness that we are Muslims.'" [Aal Imran 3:64]'"Abu Sufyan said, "When he finished his speech, the voices of the great men of Rome around him rose, and their clamor grew loud. I do not know what they said, but he ordered us to be taken out."Abu Sufyan said, "When I went out with my companions and was alone with them, I said to them, 'The matter of Ibn Abu Kabsha has become serious indeed. Even the king of Banu al-Asfar fears him.'"Abu Sufyan said, "By Allah, I remained humbled, certain that his cause would prevail, until Allah brought Islam into my heart, though I was reluctant."

حدثنا يعقوب قال حدثنا ابن أخي ابن شهاب عن عمه محمد بن مسلم قال أخبرني عبيد الله بن عبد الله بن عتبة بن مسعود أن

عبد الله بن عباس أخبره

أن رسول الله ﷺ كتب إلى قيصر يدعوه إلى الإسلام وبعث كتابه مع دحية الكلبي وأمره رسول الله ﷺ أن يدفعه إلى عظيم بصرى ليدفعه إلى قيصر فدفعه عظيم بصرى وكان قيصر لما كشف الله عز وجل عنه جنود فارس مشى من حمص إلى إيلياء على الزرابي تبسط له فقال عبد الله بن عباس فلما جاء قيصر كتاب رسول الله ﷺ قال حين قرأه التمسوا لي من قومه من أسأله عن رسول الله ﷺ قال ابن عباس فأخبرني أبو سفيان بن حرب أنه كان بالشام في رجال من قريش قدموا تجارا وذلك في المدة التي كانت بين رسول الله ﷺ وبين كفار قريش قال أبو سفيان فأتاني رسول قيصر فانطلق بي وبأصحابي حتى قدمنا إيلياء فأدخلنا عليه فإذا هو جالس في مجلس ملكه عليه التاج وإذا حوله عظماء الروم فقال لترجمانه سلهم أيهم أقرب نسبا بهذا الرجل الذي يزعم أنه نبي قال أبو سفيان أنا أقربهم إليه نسبا قال ما قرابتك منه قال قلت هو ابن عمي قال أبو سفيان وليس في الركب يومئذ رجل من بني عبد مناف غيري قال فقال قيصر أدنوه مني ثم أمر بأصحابي فجعلوا خلف ظهري عند كتفي ثم قال لترجمانه قل لأصحابه إني سائل هذا عن الرجل الذي يزعم أنه نبي فإن كذب فكذبوه قال أبو سفيان فوالله لولا الاستحياء يومئذ أن يأثر أصحابي عني الكذب لكذبته حين سألني ولكني استحيت أن يؤثر عني الكذب فصدقته عنه ثم قال لترجمانه قل له كيف نسب هذا الرجل فيكم قال قلت هو فينا ذو نسب قال فهل قال هذا القول منكم أحد قط قبله قال قلت لا قال فهل كنتم تتهمونه في الكذب قبل أن يقول ما قال قال فقلت لا قال فهل كان من آبائه من ملك قال قلت لا قال فأشراف الناس اتبعوه أم ضعفاؤهم قال قلت بل ضعفاؤهم قال فيزيدون أم ينقصون قال قلت بل يزيدون قال فهل يرتد أحد سخطة لدينه بعد أن يدخل فيه قال قلت لا قال فهل يغدر قال قلت لا ونحن الآن منه في مدة ونحن نخاف ذلك قال أبو سفيان ولم تمكني كلمة أدخل فيها شيئا أنتقصه به غيرها لأخاف أن يؤثر عني الكذب قال فهل قاتلتموه أو قاتلكم قال قلت نعم قال كيف كانت حربكم وحربه قال قلت كانت دولا سجالا ندال عليه المرة ويدال علينا الأخرى قال فبم يأمركم قال قلت يأمرنا أن نعبد الله وحده ولا نشرك به شيئا وينهانا عما كان يعبد آباؤنا ويأمرنا بالصلاة والصدق والعفاف والوفاء بالعهد وأداء الأمانة قال فقال لترجمانه حين قلت له ذلك قل له إني سألتك عن نسبه فيكم فزعمت أنه فيكم ذو نسب وكذلك الرسل تبعث في نسب قومها وسألتك هل قال هذا القول أحد منكم قط قبله فزعمت أن لا فقلت لو كان أحد منكم قال هذا القول قبله قلت رجل يأتم بقول قيل قبله وسألتك هل كنتم تتهمونه بالكذب قبل أن يقول ما قال فزعمت أن لا فقد أعرف أنه لم يكن ليذر الكذب على الناس ويكذب على الله عز وجل وسألتك هل كان من آبائه من ملك فزعمت أن لا فقلت لو كان من آبائه ملك قلت رجل يطلب ملك آبائه وسألتك أشراف الناس يتبعونه أم ضعفاؤهم فزعمت أن ضعفاءهم اتبعوه وهم أتباع الرسل وسألتك هل يزيدون أم ينقصون فزعمت أنهم يزيدون وكذلك الإيمان حتى يتم وسألتك هل يرتد أحد سخطة لدينه بعد أن يدخل فيه فزعمت أن لا وكذلك الإيمان حين يخالط بشاشة القلوب لا يسخطه أحد وسألتك هل يغدر فزعمت أن لا وكذلك الرسل وسألتك هل قاتلتموه وقاتلكم فزعمت أن قد فعل وأن حربكم وحربه يكون دولا يدال عليكم المرة وتدالون عليه الأخرى وكذلك الرسل تبتلى ويكون لها العاقبة وسألتك بماذا يأمركم فزعمت أنه يأمركم أن تعبدوا الله عز وجل وحده لا تشركوا به شيئا وينهاكم عما كان يعبد آباؤكم ويأمركم بالصدق والصلاة والعفاف والوفاء بالعهد وأداء الأمانة وهذه صفة نبي قد كنت أعلم أنه خارج ولكن لم أظن أنه منكم فإن يكن ما قلت فيه حقا فيوشك أن يملك موضع قدمي هاتين والله لو أرجو أن أخلص إليه لتجشمت لقيه ولو كنت عنده لغسلت عن قدميه قال أبو سفيان ثم دعا بكتاب رسول الله ﷺ فأمر به فقرئ فإذا فيه بسم الله الرحمن الرحيم من محمد عبد الله ورسوله إلى هرقل عظيم الروم سلام على من اتبع الهدى أما بعد فإني أدعوك بدعاية الإسلام أسلم تسلم وأسلم يؤتك الله أجرك مرتين فإن توليت فعليك إثم الأريسيين يعني الأكارة و {يا أهل الكتاب تعالوا إلى كلمة سواء بيننا وبينكم ألا نعبد إلا الله ولا نشرك به شيئا ولا يتخذ بعضنا بعضا أربابا من دون الله فإن تولوا فقولوا اشهدوا بأنا مسلمون} قال أبو سفيان فلما قضى مقالته علت أصوات الذين حوله من عظماء الروم وكثر لغطهم فلا أدري ماذا قالوا وأمر بنا فأخرجنا قال أبو سفيان فلما خرجت مع أصحابي وخلصت لهم قلت لهم أمر أمر ابن أبي كبشة هذا ملك بني الأصفر يخافه قال أبو سفيان فوالله ما زلت ذليلا مستيقنا أن أمره سيظهر حتى أدخل الله قلبي الإسلام وأنا كاره