Asim bin Kulayb narrates from his father, who narrates from a man of the Ansar, who said: We went out with the Messenger of Allah (peace and blessings be upon him) for a funeral, and I was a boy with my father. He (peace and blessings be upon him) sat at the edge of the grave pit and was saying to those digging it: "Make it wide at the head side, make it wide at the feet side; many a cluster (of dates) will be his in Paradise."
In a narration of Abu Abdullah: I saw him sitting at the edge of the grave pit, and he (peace and blessings be upon him) said: "Make it wide at his head side; many a cluster will be his in Paradise."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6755