(10) باب كَيْفَ كَانَ صَلاَةُ النَّبِيِّ صلى الله عليه وسلم وَكَمْ كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي مِنَ اللَّيْلِ
Narrated Ibn `Abbas:
The prayer of the Prophet (ﷺ) used to be of thirteen rak`at, i.e. of the night prayer.
Reference: Sahih al-Bukhari 1138
In-book reference: Book 19, Hadith 19
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 21, Hadith 239