Sahih al-Bukhari, Volume 1, Book 8, Hadith 421 (USC-MSA) ⓘ
Narrated Abu Al-Taiyah [??]: Anas said, "The Prophet prayed in the sheep fold." Later on I heard him saying, "He prayed in the sheep folds before the construction of the, mosque."
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي التَّيَّاحِ، عَنْ أَنَسٍ، قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم يُصَلِّي فِي مَرَابِضِ الْغَنَمِ، ثُمَّ سَمِعْتُهُ بَعْدُ يَقُولُ كَانَ يُصَلِّي فِي مَرَابِضِ الْغَنَمِ قَبْلَ أَنْ يُبْنَى الْمَسْجِدُ.
also referenced under: Book 8, Hadith 79 (In-Book) & Hadith 429 (DarusSalam)