حَدَّثَنَا أَبُو الْيَمَانِ، قَالَ: أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ قَالَ: أَخْبَرَنِي عُبَيْدُ اللهِ بْنُ عَبْدِ اللهِ بْنِ عُتْبَةَ، أَنَّ عَبْدَ اللهِ بْنَ عَبَّاسٍ أَخْبَرَهُ، أَنَّ أَبَا سُفْيَانَ بْنَ حَرْبٍ أَخْبَرَهُ: أَرْسَلَ إِلَيْهِ هِرَقْلُ مَلِكُ الرُّومِ، ثُمَّ دَعَا بِكِتَابِ رَسُولِ اللهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الَّذِي أُرْسِلَ بِهِ مَعَ دِحْيَةَ الْكَلْبِيِّ إِلَى عَظِيمِ بُصْرَى، فَدَفَعَهُ إِلَيَّ هِرَقْلُ فَقَرَأَهُ، فَإِذَا فِيهِ: ”بِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ، مِنْ مُحَمَّدٍ عَبْدِ اللهِ وَرَسُولِهِ إِلَى هِرَقْلَ عَظِيمِ الرُّومِ، سَلاَّمٌ عَلَى مَنِ اتَّبَعَ الْهُدَى، أَمَّا بَعْدُ، فَإِنِّي أَدْعُوكَ بِدِعَايَةِ الإِسْلاَمِ، أَسْلِمْ تَسْلَمْ، يُؤْتِكَ اللَّهُ أَجْرَكَ مَرَّتَيْنِ، فَإِنْ تَوَلَّيْتَ فَإِنَّ عَلَيْكَ إِثْمَ الأَرِيسِيِّينَ وَ ﴿يَا أَهْلَ الْكِتَابِ تَعَالَوْا إِلَى كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ﴾ إِلَى قَوْلِهِ: ﴿اشْهَدُوا بِأَنَّا مُسْلِمُونَ﴾ [آل عمران: 64].“
It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them) that the king of Rome, Heraclius, summoned Sayyiduna Abu Sufyan (may Allah be pleased with him), then he asked for the letter of the Messenger of Allah (peace and blessings be upon him) that had been sent to him. This letter the Prophet (peace and blessings be upon him) had instructed Sayyiduna Dihyah Kalbi (may Allah be pleased with him) to give to the governor of Busra, so he delivered it to Heraclius, and he read it. In it was: «بسم الله الرحمن الرحیم» ...... From the servant of Allah and His Messenger, Muhammad, to Heraclius, the king of Rome. Peace be upon him who follows guidance. Verily, I invite you to Islam. Accept Islam, you will be safe, and Allah the Exalted will grant you a double reward, and if you refuse, then the sin of your subjects will be upon you. And O People of the Book, come to a word that is equitable between us and you ...... you will bear witness that we are Muslims.
Related hadith on this topic