Hadithcore
Sahih al-Bukhari, 4140
sahih

Narrated Jabir bin `Abdullah Al-Ansari:

I saw the Prophet (ﷺ) offering his Nawafil prayer on his Mount facing the East during the Ghazwa of Anmar.

حَدَّثَنَا آدَمُ، حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، حَدَّثَنَا عُثْمَانُ بْنُ عَبْدِ اللَّهِ بْنِ سُرَاقَةَ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ الأَنْصَارِيِّ، قَالَ رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم فِي غَزْوَةِ أَنْمَارٍ يُصَلِّي عَلَى رَاحِلَتِهِ، مُتَوَجِّهًا قِبَلَ الْمَشْرِقِ مُتَطَوِّعًا‏.‏

References2 variants
In-Book Reference
Book 64, Hadith 184
USC-MSA web (English) reference
Vol. 5, Book 59, Hadith 461 (deprecated numbering scheme)