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 unto 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 Jehovah said unto Moses, Speak unto the priests, the sons of Aaron, and say unto them, There shall none defile himself for the dead among his people;
Leviticus 21:10-12
And he that is the high priest among his brethren, upon whose head the anointing oil is poured, and that is consecrated to put on the garments, shall not let the hair of his head go loose, nor rend 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 that hath had no husband, they may defile themselves.