Language:
كتاب الصلاة
8  
Prayers (Salat)
(92)
Chapter: To offer As-Salat (the prayer) using a Harba (a short spear) (as a Sutra)
(92)
باب الصَّلاَةِ إِلَى الْحَرْبَةِ
Sahih al-Bukhari 498

Narrated `Abdullah:

The Prophet (ﷺ) used to get a Harba planted in front of him (as a Sutra) and pray behind it.

حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، أَخْبَرَنِي نَافِعٌ، عَنْ عَبْدِ اللَّهِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يُرْكَزُ لَهُ الْحَرْبَةُ فَيُصَلِّي إِلَيْهَا‏.‏
Reference : Sahih al-Bukhari 498
In-book reference : Book 8, Hadith 145
USC-MSA web (English) reference : Vol. 1, Book 9, Hadith 477
  (deprecated numbering scheme)