“The priest who is chief among his brothers, on whose head the anointing oil is poured and who has been consecrated to wear the garments, shall not let the hair of his head hang loose nor tear his clothes.
More was expected from a priest than from other people, but more from the high priest than from other priests, because upon his head the anointing oil was poured, and he was consecrated to put on the garments (Lev 21:10), both which were typical of the anointing and adorning of the Lord Jesus, with all the gifts and graces of the Holy Spirit, which he received without measure.
Commenting on Leviticus 21:10-15
And he that is the high priest among his brethren,.... Either among his brethren, the priests, being in office above them; or among his brethren the Israelites, among and over whom he is high priest; or, as others render it, "the priest who is greater than his brethren" (d), in an higher office; the Jews say (e) the high priest was to be greater than...
he that is the high priest among his brethren . . . shall not uncover his head, nor rend his clothes--The indulgence in the excepted cases of family bereavement, mentioned above [Lev 21:2-3], which was granted to the common priests, was denied to him; for his absence from the sanctuary for the removal of any contracted defilement could not have been dispensed with, neither could...