He shall not go out of the sanctuary, lest he profane the sanctuary of his God, for the consecration of the anointing oil of his God is on him: I am the LORD.
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
Neither shall he go out of the sanctuary,.... In the time of service, upon any occasion whatever; otherwise, when there was a necessity for it, he might go out from thence, though this was rarely done, and only in the night time: Maimonides (m) says he had a house prepared for him in the sanctuary, called the chamber of the high priest; and it was...
Neither shall he go out of the sanctuary, nor profane the sanctuary of his God; for the crown of the anointing oil of his God [is] upon him: I [am] the LORD. (h) To go to the dead. (i) For by his anointing he was preferred above the other priests and therefore could not lament the dead, least he should have polluted his holy anointing.