Abu Dawud
Funerals
Book Number: 014 / Hadith Number: 3206
Narated By Al-Bara' ibn Azib : We went out with the Apostle of Allah (pbuh) to the funeral of a man of the Ansar, but when we reached the grave, the niche in the side had not yet been made, so the Prophet (pbuh) sat down facing the qiblah, and we sat down along with him.