They shall not make baldness - See the note on Leviticus 19:27. It is supposed that these things were particularly prohibited, because used superstitiously by the Egyptian priests, who, according to Herodotus, shaved the whole body every third day, that there might be no uncleanness about them when they ministered in their temples. This appears to have been a general custom among the heathen. In the book of Baruch 6:31, the priests of Babylon are represented sitting in their temples, with their clothes rent, and their heads and beards shaven, and having nothing upon their heads. Every person knows the tonsure of the Catholic priests. Should not this be avoided as an approach to a heathenish custom?
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.