Sahih al-Bukhari, Book 23, Hadith 83 (In-Book) ⓘ
Narrated 'Amir: Ibn `Abbas (who was at that time a boy) said, "Allah's Messenger came to a grave and the people said, 'He or she was buried yesterday.' " Ibn `Abbas added, "We aligned behind the Prophet and he led the funeral prayer of the deceased."
حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا يَحْيَى بْنُ أَبِي بُكَيْرٍ، حَدَّثَنَا زَائِدَةُ، حَدَّثَنَا أَبُو إِسْحَاقَ الشَّيْبَانِيُّ، عَنْ عَامِرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ أَتَى رَسُولُ اللَّهِ صلى الله عليه وسلم قَبْرًا، فَقَالُوا هَذَا دُفِنَ، أَوْ دُفِنَتِ الْبَارِحَةَ. قَالَ ابْنُ عَبَّاسٍ ـ رضى الله عنهما ـ فَصَفَّنَا خَلْفَهُ ثُمَّ صَلَّى عَلَيْهَا.
also referenced under: Hadith 1326 (DarusSalam) & Volume 2, Book 23, Hadith 411 (USC-MSA)