Sunan an-Nasa'i, Volume 2, Book 19, Hadith 1566 (DarusSalam) ⓘ
It was narrated from Ibn 'Umar that: The Messenger of Allah used to take out an 'Anazah (a short spear) on the day of Al-Fitr and the day of Al-Adha, plant it in the ground, and pray facing toward it.
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَنْبَأَنَا مَعْمَرٌ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُخْرِجُ الْعَنَزَةَ يَوْمَ الْفِطْرِ وَيَوْمَ الأَضْحَى يُرْكِزُهَا فَيُصَلِّي إِلَيْهَا .
also referenced under: Hadith 1565 (Reference) & Book 19, Hadith 10 (In-Book)