Exodus 19:22

Let - To hinder or obstruct.

Sanctify - To be sacred and set apart.

Let the priests also - sanctify themselves - That there were priests among the Hebrews before the consecration of Aaron and his sons, cannot be doubted; though their functions might be in a considerable measure suspended while under persecution in Egypt, yet the persons existed whose right and duty it was to offer sacrifices to God. Moses requested liberty from Pharaoh to go into the wilderness to sacrifice; and had there not been among the people both sacrifices and priests, the request itself must have appeared nugatory and absurd. Sacrifices from the beginning had constituted an essential part of the worship of God, and there certainly were priests whose business it was to offer them to God before the giving of the law; though this, for especial reasons, was restricted to Aaron and his sons after the law had been given. As sacrifices had not been offered for a considerable time, the priests themselves were considered in a state of impurity; and therefore God requires that they also should be purified for the purpose of approaching the mountain, and hearing their Maker promulgate his laws. See Clarke's note on Exodus 28:1.

The priests also - Sacrifices had hitherto been offered by firstborn, or the heads of families. See Genesis 14:18 note.