Exodus 19:22

The priests also. Special mention of the “priests” would indicate that the urge to trespass was particularly strong among them. Trained as they were to exercise sacred functions, they may have considered themselves practically equal to Moses and Aaron. They may have resented their exclusion from the divine presence. Were they not the appointed intermediaries between God and man?

Sanctify themselves. It would seem from this command that the priests had not regarded the injunction of v. 10 as applying to them, and so did not comply with it. Hence the charge to do so was directed specially to them. Holiness of office does not necessarily mean holiness in the individual who holds it. Ministers of God are not given any special immunity from iniquity, as the Scriptures often demonstrate (see Lev. 10:1, 2; 1 Sam. 2:12-17; 4:17). This verse and Ex. 24:5 show that there were those set aside for priestly services before the institution of the Levitical order (see PP 350).