Sunan an-Nasai 15485
In-book no 749أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، قَالَ أَنْبَأَنَا نَافِعٌ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ كَانَ يَرْكُزُ الْحَرْبَةَ ثُمَّ يُصَلِّي إِلَيْهَا .
Narrated Ibn Umar: It was narrated from Ibn Umar concerning the Messenger of Allah (ﷺ) he said: "He used to set up a short spear then pray facing toward it."