1. Sahl ibn Ziyad has said that according to the narration of our people:the depth of the grave is up to one’s collarbones. Certain ones have said that it is up to one’s chest and still others say that it is up to the whole height of a man, so one can pull the sheet over the head of those in the grave. The depth of Lahad is as high as one can sit straight inside. He (the narrator) has said that when Ali ibn al-Husayn, ‘Alayhi al-Salam, was about to die, he fainted for a while and then he removed the cloth and said, ‘All praise belongs to Allah who has made us heirs of paradise. We can live wherever we like and this is good reward for those who do good deeds.’ He (the Imam) then said, ‘Dig for me (a grave) and sprinkle water properly.’ He (the narrator) has said that he (the Imam), ‘Alayhi al-Salam, then pulled the sheet over his face and passed away.’” (Shahid al-Thani has said that fainting of the Imam in this Hadith is not in a literal sense; as long as an Imam is alive he is responsible and in a fainting condition one is not responsible). (Lahad is a prepared room horizontally at the bottom of the grave as opposed to a vertical ditch in the center of the grave)
