Sunan Ibn Majah 870
سنن ابن ماجه#870Sahihحَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، وَعَمْرُو بْنُ عَبْدِ اللَّهِ، قَالاَ حَدَّثَنَا وَكِيعٌ، عَنِ الأَعْمَشِ، عَنْ عُمَارَةَ، عَنْ أَبِي مَعْمَرٍ، عَنْ أَبِي مَسْعُودٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لاَ تُجْزِئُ صَلاَةٌ لاَ يُقِيمُ الرَّجُلُ فِيهَا صُلْبَهُ فِي الرُّكُوعِ وَالسُّجُودِ " .
It was narrated that Abu Mas’ud said:“The Messenger of Allah (ﷺ) said: ‘No prayer is acceptable in which a man does not settle his spine when bowing and when prostrating.’”
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — 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. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Muhammad Fouad Abd al-Baqi, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 5:68