Sunan an-Nasa'i 224
سنن النسائي#224Sahihأَخْبَرَنَا مُجَاهِدُ بْنُ مُوسَى، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، قَالَ حَدَّثَنِي يَحْيَى بْنُ الْوَلِيدِ، قَالَ حَدَّثَنِي مُحِلُّ بْنُ خَلِيفَةَ، قَالَ حَدَّثَنِي أَبُو السَّمْحِ، قَالَ كُنْتُ أَخْدُمُ رَسُولَ اللَّهِ صلى الله عليه وسلم فَكَانَ إِذَا أَرَادَ أَنْ يَغْتَسِلَ قَالَ " وَلِّنِي قَفَاكَ " . فَأُوَلِّيهِ قَفَاىَ فَأَسْتُرُهُ بِهِ .
Abu As-Samh said:"I used to serve the Messenger of Allah (ﷺ) and when he wanted to perform Ghusl he said: 'Turn your back.' So I turned my back to him and concealed him
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: 1:225