Sunan Abi Dawud 1226
سنن أبي داود#1226Sahihحَدَّثَنَا الْقَعْنَبِيُّ، عَنْ مَالِكٍ، عَنْ عَمْرِو بْنِ يَحْيَى الْمَازِنِيِّ، عَنْ أَبِي الْحُبَابِ، سَعِيدِ بْنِ يَسَارٍ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يُصَلِّي عَلَى حِمَارٍ وَهُوَ مُتَوَجِّهٌ إِلَى خَيْبَرَ .
Narrated 'Abd Allah b. 'Umar:I saw the Messenger of Allah (ﷺ) praying on a donkey while he was facing Khaibar
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih Muslim (700)
In-book reference: 4:29