Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
tirmidhi:2717 – Sūwayd b. Naṣr > ʿAbdullāh b. al-Mubārak > Yūnus > al-Zuhrī > ʿUbaydullāh b. ʿAbdullāh b. ʿUtbah > Ibn ʿAbbās > Abū Sufyān b. Ḥarb

that Abu Sufyan bin Harb informed him that Hiraql had sent for him while he was with a party of the Quraish, and they were trading in Ash-Sham, so they went to him." And he mentioned the Hadith and said: "Then he called for the letter of the Messenger of Allah ﷺ to be read, and it said in it: 'In the Name of Allah, the Merciful, the Beneficent. From Muhammad, Allah's Slave and His Messenger, to Hiraql the leader of Rome. Peace be upon whoever follows the guidance. To proceed:"  

الترمذي:٢٧١٧ – حَدَّثَنَا سُوَيْدُ بْنُ نَصْرٍ أَنْبَأَنَا عَبْدُ اللَّهِ بْنُ الْمُبَارَكِ أَنْبَأَنَا يُونُسُ عَنِ الزُّهْرِيِّ أَخْبَرَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُتْبَةَ عَنِ ابْنِ عَبَّاسٍ أَنَّهُ أَخْبَرَهُ أَنَّ أَبَا سُفْيَانَ بْنَ حَرْبٍ

أَخْبَرَهُ أَنَّ هِرَقْلَ أَرْسَلَ إِلَيْهِ فِي نَفَرٍ مِنْ قُرَيْشٍ وَكَانُوا تُجَّارًا بِالشَّامِ فَأَتَوْهُ فَذَكَرَ الْحَدِيثَ قَالَ ثُمَّ دَعَا بِكِتَابِ رَسُولِ اللَّهِ ﷺ فَقُرِئَ فَإِذَا فِيهِ بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ مِنْ مُحَمَّدٍ عَبْدِ اللَّهِ وَرَسُولِهِ إِلَى هِرَقْلَ عَظِيمِ الرُّومِ السَّلاَمُ عَلَى مَنِ اتَّبَعَ الْهُدَى أَمَّا بَعْدُ  

قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ وَأَبُو سُفْيَانَ اسْمُهُ صَخْرُ بْنُ حَرْبٍ

See similar narrations below:

Collected by Bukhārī
bukhari:6260 – Muḥammad b. Muqātil Abū al-Ḥasan > ʿAbdullāh > Yūnus > al-Zuhrī > ʿUbaydullāh b. ʿAbdullāh b. ʿUtbah > Ibn ʿAbbās > Abū Sufyān b. Ḥarb

that Heraclius had sent for him to come along with a group of the Quraish who were trading in Sha'm, and they came to him. Then Abu Sufyan mentioned the whole narration and said, "Heraclius asked for the letter of Messenger of Allah ﷺ . When the letter was read, its contents were as follows: 'In the name of Allah, the Beneficent, the Merciful. From Muhammad, Allah's slave and His Apostle to Heraclius, the Chief of Byzantines: Peace be upon him who follows the right path (guidance)! Amma ba'du (to proceed )...' (See Hadith No 6, Vol 1 for details)  

البخاري:٦٢٦٠ – حَدَّثَنَا مُحَمَّدُ بْنُ مُقَاتِلٍ أَبُو الْحَسَنِ أَخْبَرَنَا عَبْدُ اللَّهِ أَخْبَرَنَا يُونُسُ عَنِ الزُّهْرِيِّ قَالَ أَخْبَرَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُتْبَةَ أَنَّ ابْنَ عَبَّاسٍ أَخْبَرَهُ أَنَّ أَبَا سُفْيَانَ بْنَ حَرْبٍ

أَخْبَرَهُ أَنَّ هِرَقْلَ أَرْسَلَ إِلَيْهِ فِي نَفَرٍ مِنْ قُرَيْشٍ وَكَانُوا تِجَارًا بِالشَّأْمِ فَأَتَوْهُ فَذَكَرَ الْحَدِيثَ قَالَ ثُمَّ دَعَا بِكِتَابِ رَسُولِ اللَّهِ ﷺ فَقُرِئَ فَإِذَا فِيهِ بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ مِنْ مُحَمَّدٍ عَبْدِ اللَّهِ وَرَسُولِهِ إِلَى هِرَقْلَ عَظِيمِ الرُّومِ السَّلاَمُ عَلَى مَنِ اتَّبَعَ الْهُدَى أَمَّا بَعْدُ