Sunan Ibn Majah 966
سنن ابن ماجه#966Hasanحَدَّثَنَا أَبُو سَعِيدٍ، سُفْيَانُ بْنُ زِيَادٍ الْمُؤَدِّبُ حَدَّثَنَا مُحَمَّدُ بْنُ رَاشِدٍ، عَنِ الْحَسَنِ بْنِ ذَكْوَانَ، عَنْ عَطَاءٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ نَهَى رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ أَنْ يُغَطِّيَ الرَّجُلُ فَاهُ فِي الصَّلاَةِ .
It was narrated that Abu Hurairah said:“The Messenger of Allah (ﷺ) forbade a man to cover his mouth during the prayer.”
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-AlbaniHasan
Muhammad Fouad Abd al-BaqiHasan
Shuaib Al ArnautDaif
Zubair Ali ZaiDaif
In-book reference: 5:164