Sahih al-Bukhari, Volume 1, Book 12, Hadith 830 (USC-MSA) ⓘ
Narrated Anas: The Prophet prayed in the house of Um Sulaim; and I, along with an orphan stood behind him while Um Sulaim (stood) behind us.
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا ابْنُ عُيَيْنَةَ، عَنْ إِسْحَاقَ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ صَلَّى النَّبِيُّ صلى الله عليه وسلم فِي بَيْتِ أُمِّ سُلَيْمٍ، فَقُمْتُ وَيَتِيمٌ خَلْفَهُ، وَأُمُّ سُلَيْمٍ خَلْفَنَا.
also referenced under: Book 10, Hadith 262 (In-Book) & Hadith 871 (DarusSalam)