The Two Festivals (Eids)
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.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
From Sahih al-Bukhari, whose reports the scholars accept as authentic.