Albert Barnes Commentary Leviticus 21:5

"They shall not make baldness upon their head, neither shall they shave off the corner of their beard, nor make any cuttings in their flesh." — Leviticus 21:5 (ASV)

These prohibitions given to the people at large (compare the margin reference) had a special fitness for the Hebrew priests. They were the instruments of the divine will for averting death; all their sacrifices were a type of the death of Christ, which swallowed up death in victory (1 Corinthians 15:54–57), and it would therefore have been unsuitable that they should have the same freedom as other people to become mourners.