While Messenger of Allah ﷺ was carrying stones (along) with the people of Mecca for (the building of) the Kaʿba wearing an Izar (waist-sheet cover), his uncle Al-ʿAbbas said to him, "O my nephew! (It would be better) if you take off your Izar and put it over your shoulders underneath the stones." So he took off his Izar and put it over his shoulders, but he fell unconscious and since then he had never been seen naked.  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يَنْقُلُ مَعَهُمُ الْحِجَارَةَ لِلْكَعْبَةِ وَعَلَيْهِ إِزَارُهُ فَقَالَ لَهُ الْعَبَّاسُ عَمُّهُ يَا ابْنَ أَخِي لَوْ حَلَلْتَ إِزَارَكَ فَجَعَلْتَ عَلَى مَنْكِبَيْكَ دُونَ الْحِجَارَةِ قَالَ فَحَلَّهُ فَجَعَلَهُ عَلَى مَنْكِبَيْهِ فَسَقَطَ مَغْشِيًّا عَلَيْهِ فَمَا رُئِيَ بَعْدَ ذَلِكَ عُرْيَانًا ﷺ