Sunan an-Nasa'i 1451
سنن النسائي#1451Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ سَلَمَةَ، قَالَ حَدَّثَنَا ابْنُ وَهْبٍ، عَنْ يُونُسَ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُمَرَ، عَنْ أَبِيهِ، قَالَ صَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم بِمِنًى رَكْعَتَيْنِ وَصَلاَّهَا أَبُو بَكْرٍ رَكْعَتَيْنِ وَصَلاَّهَا عُمَرُ رَكْعَتَيْنِ وَصَلاَّهَا عُثْمَانُ صَدْرًا مِنْ خِلاَفَتِهِ .
Ubaidullah bin 'Abdullah bin Umar narrated that:His father said: "The Messenger of Allah (ﷺ) prayed two rak'ahs in Mina, and Abu Bakr prayed two rak'ahs, and Umar prayed two rak'ahs, and Uthman prayed (two rak'ahs) at the beginning of his Khilafah
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:
In-book reference: 15:19