Sahih Bukhari
Sahih Bukhari Volume 007, Book 072, Hadith Number 712.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 72. Dress
Narrated By Abu Said Al-Khudri : The Prophet forbade Ishtimal-as-Samma' and that a man should sit in an Ihtiba' posture in one garment, nothing of which covers his private parts.