Sunan an-Nasa'i 608
سنن النسائي#608Sahihأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الأَعْمَشِ، عَنْ عُمَارَةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ يَزِيدَ، عَنْ عَبْدِ اللَّهِ، قَالَ مَا رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم جَمَعَ بَيْنَ صَلاَتَيْنِ إِلاَّ بِجَمْعٍ وَصَلَّى الصُّبْحَ يَوْمَئِذٍ قَبْلَ وَقْتِهَا .
It was narrated that 'Abdullah said:"I never saw the Messenger of Allah (ﷺ) combine any two prayers except in Al-Muzdalifah, and on that day he prayed Subh before its time
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:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 6:115