Sunan an-Nasa'i 5341
سنن النسائي#5341Sahihأَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ أَنْبَأَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ عَطَاءِ بْنِ يَزِيدَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ اشْتِمَالِ الصَّمَّاءِ وَأَنْ يَحْتَبِيَ الرَّجُلُ فِي ثَوْبٍ وَاحِدٍ لَيْسَ عَلَى فَرْجِهِ مِنْهُ شَىْءٌ .
It was narrated that Abu Sa'eed Al-Khudri said:"The Messenger of Allah [SAW] forbade Ishtimal As-Samma' and wrapping oneself in a single garment (that did not cover the private parts)
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: 48:302