(58) باب نَوْمِ الرِّجَالِ فِي الْمَسْجِدِ
Narrated Abu Huraira:
I saw seventy of As-Suffa men and none of them had a Rida' (a garment covering the upper part of the body). They had either Izars (only) or sheets which they tied round their necks. Some of these sheets reached the middle of their legs and some reached their heels and they used to gather them with their hands lest their private parts should become naked.
Reference: Sahih al-Bukhari 442
In-book reference: Book 8, Hadith 91
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 8, Hadith 433