Leviticus 21:1-4, 10-12

GOD spoke to Moses: “Speak to the priests, the sons of Aaron. Tell them, A priest must not ritually contaminate himself by touching the dead, except for close relatives: mother, father, son, daughter, brother, or an unmarried sister who is dependent on him since she has no husband; for these he may make himself ritually unclean, but he must not contaminate himself with the dead who are only related to him by marriage and thus profane himself.

“The high priest, the one among his brothers who has received the anointing oil poured on his head and been ordained to wear the priestly vestments, must not let his hair go wild and tangled nor wear ragged and torn clothes. He must not enter a room where there is a dead body. He must not ritually contaminate himself, even for his father or mother; and he must neither abandon nor desecrate the Sanctuary of his God because of the dedication of the anointing oil which is upon him. I am GOD.