Sahih Bukhari Volume 5, Book 58, Hadith Number 170.

Narated By Jabir bin ‘Abdullah : When the Ka’ba was rebuilt, the Prophet and ‘Abbas went to carry stones. ‘Abbas said to the Prophet “(Take off and) put your waist sheet over your neck so that the stones may not hurt you.” (But as soon as he took off his waist sheet) he fell unconscious on the ground with both his eyes towards the sky. When he came to his senses, he said, “My waist sheet! My waist sheet!” Then he tied his waist sheet (round his waist).