Sahih Al Bukhari – Book of Prayers (Salat)
Volumn 001, Book 008, Hadith Number 464.
—————————————–
Narated By 'Abbad bin Tamim : That his uncle said, "I saw Allah's Apostle lying flat (on his back) in the mosque with one leg on the other." Narrated Said bin Al-Musaiyab that 'Umar and 'Uthman used to do the same.
