It was narrated that Ibn ‘Umar said:“When the Prophet (ﷺ) prayed on the day of ‘Eid or on another occasion, a small spear was set up in front of him, and he prayed facing it, and the people were behind him.” Nafi` said: It is from here that the leaders have taken this practice.
حَدَّثَنَا سُوَيْدُ بْنُ سَعِيدٍ، حَدَّثَنَا عَلِيُّ بْنُ مُسْهِرٍ، عَنْ عُبَيْدِ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ كَانَ النَّبِيُّ ـ صلى الله عليه وسلم ـ إِذَا صَلَّى يَوْمَ عِيدٍ أَوْ غَيْرَهُ نُصِبَتِ الْحَرْبَةُ بَيْنَ يَدَيْهِ فَيُصَلِّي إِلَيْهَا وَالنَّاسُ مِنْ خَلْفِهِ . قَالَ نَافِعٌ فَمِنْ ثَمَّ اتَّخَذَهَا الأُمَرَاءُ .
IbnMaja
Establishing the Prayer and the Sunnah Regarding Them • Hadith 1305