The priests were required to maintain personal fleshly cleanliness and high moral standards. When entering the tent of meeting and before presenting an offering at the altar, they were to wash their hands and feet at the basin in the courtyard “that they [might] not die.” (Ex 30:17-21; 40:30-32)

They could not defile themselves by touching a corpse or mourning for the dead; this would make them temporarily unclean for service. The underpriests (but not the high priest) might do so, however, for one in very close family relationship: mother, father, son, daughter, brother, or virgin sister who was close to (apparently, living with or near) him; also the wife was possibly included as one close to him. (Le 21:1-4) Any priest who became unclean, by leprosy, by a running discharge, or by a corpse or other unclean thing, could not eat of the holy things or perform sanctuary service until cleansed, otherwise he must die.​—Le 22:1-9.