(9) باب يَنْزِلُ لِلْمَكْتُوبَةِ
Narrated Jabir bin `Abdullah:
The Prophet (ﷺ) used to pray (the Nawafil) on his Mount facing east and whenever he wanted to offer the compulsory prayer, he used to dismount and face the Qibla.
Reference: Sahih al-Bukhari 1099
In-book reference: Book 18, Hadith 19
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 20, Hadith 203