Verse 1
LEVITICUS- TWENTY-ONE
Verses 1-6:
The priests were to be ceremonially clean, in order to officiate in their prescribed duties. Because any contact with a dead body resulted in legal ceremonial uncleanness, they were forbidden to take part in any funeral rites, except in the case of immediate family members. Shaving of the head, the certain ways of trimming the beard were funeral customs, see Le 19:27, 28.
The reason for this prohibition: they were especially dedicated to Jehovah Elohim and His service, and they must act with gravity and sobriety at all times.
Christians today belong to the Lord. For that reason, they are to act with sobriety at all times, see 1Co 9:25-27; 2Co 5:13.