It is narrated from Hazrat Ali (may Allah be pleased with him). He says that the Messenger of Allah (peace and blessings be upon him) sacrificed a goat as 'aqiqah on behalf of Hasan. And he said, "O Fatimah! Shave his head and give charity equal to the weight of his hair." So they weighed the hair, and its weight was a dirham or a few dirhams.