He shall not make himself unclean for his father, mother, brother, or sister, when they die, because his separation and abstinence to his God is upon his head.
And they shall go near to no dead person to defile themselves, except for father or for mother, for son or for daughter, for brother or for sister who has had no husband; for them they may defile themselves. [Lev. 21:1, 2.]
And there were certain men who were defiled by touching the dead body of a man, so they could not keep the Passover on that day; and they came before Moses and Aaron on that day.