Sahih al-Bukhari, Book 23, Hadith 80 (In-Book) ⓘ

Narrated Ash-Shaibani: Ash-Shu`bi said, "Somebody who passed along with your Prophet (p.b.u.h) by a grave that was separate from the other graves informed me (saying), "The Prophet led us (in the prayer) and we aligned behind him." We said, "O Abu `Amr! Who told you this narration?" He replied, "Ibn `Abbas."

حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا شُعْبَةُ، عَنِ الشَّيْبَانِيِّ، عَنِ الشَّعْبِيِّ، قَالَ أَخْبَرَنِي مَنْ، مَرَّ مَعَ نَبِيِّكُمْ صلى الله عليه وسلم عَلَى قَبْرٍ مَنْبُوذٍ فَأَمَّنَا فَصَفَفْنَا خَلْفَهُ‏.‏ فَقُلْنَا يَا أَبَا عَمْرٍو مَنْ حَدَّثَكَ قَالَ ابْنُ عَبَّاسٍ رضى الله عنهما‏.‏