Imam Bukhari : 4659

حَدَّثَنَا آدَمُ بْنُ أَبِي إِيَاسٍ حَدَّثَنَا شُعْبَةُ حَدَّثَنَا أَبُو إِيَاسٍ قَالَ سَمِعْتُ عَبْدَ اللَّهِ بْنَ مُغَفَّلٍ قَالَرَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقْرَأُ وَهُوَ عَلَى نَاقَتِهِ أَوْ جَمَلِهِ وَهِيَ تَسِيرُ بِهِ وَهُوَ يَقْرَأُ سُورَةَ الْفَتْحِ أَوْ مِنْ سُورَةِ الْفَتْحِ قِرَاءَةً لَيِّنَةً يَقْرَأُ وَهُوَ يُرَجِّعُ

Narrated to us Adam bin Abu Iyas, narrated to us Shu'bah, narrated to us Abu Iyas, he said I heard Abdullah bin Mughaffal say, "I saw the Prophet peace be upon him reciting while on his camel or she-camel as it walked, reciting Surah Al-Fath or part of Surah Al-Fath, softly and with repetition.