Numbers 6:7
He shall not make himself unclean for his father, or for his mother, for his brother, or for his sister, when they die, because his separation to God is upon his head.
Numbers 9:6
And there were certain men who were unclean by reason of the dead body of a man, so that they could not keep the Passover on that day. And they came before Moses and before Aaron on that day,
Leviticus 21:1-2
And LORD said to Moses, Speak to the priests, the sons of Aaron, and say to them, There shall none defile himself for the dead among his people,
Leviticus 21:10-12
And he who is the high priest among his brothers, upon whose head the anointing oil is poured, and who is consecrated to put on the garments, shall not let the hair of his head go loose, nor tear his clothes,
Ezekiel 44:25
And they shall go in to no dead person to defile themselves. But for father, or for mother, or for son, or for daughter, for brother, or for sister who has had no husband, they may defile themselves.