Ibn ‘Abbas said that God's messenger came upon a grave where an interment had taken place at night and asked when this person had been buried. On being told that he had been buried the previous night, he asked why they had not informed him. They told him that they had conducted the burial in the darkness of night and had not liked to waken him, whereupon he stood up, and when they formed a row behind him he prayed over the dead. (Bukharl and Muslim.)