Sahih al-Bukhari, Volume 2, Book 15, Hadith 89 (USC-MSA) ⓘ
Narrated Ibn `Umar: On the day of `Id-ul-Fitr and `Id-ul-Adha a spear used to be planted in front of the Prophet (as a Sutra for the prayer) and then he would pray.
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا عَبْدُ الْوَهَّابِ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ تُرْكَزُ الْحَرْبَةُ قُدَّامَهُ يَوْمَ الْفِطْرِ وَالنَّحْرِ ثُمَّ يُصَلِّي.
also referenced under: Book 13, Hadith 21 (In-Book) & Hadith 972 (DarusSalam)