Read: Leviticus 21
They must be holy to their God and must not profane the name of their God. Lev 21:6a
In the Gospel according to Leviticus, we come to a section which is specifically addressed to priests, to Aaron the high priest and his sons. This family was set aside in Israel to do a specific work of ministry in relationship to God. All the members of Aaron’s family were priests by birth. They did not become priests by choice or by desire on their part, but by being born into the family of Aaron. There was no other way to become a priest. No other family was ever recognized as having valid membership in the priesthood.
But even though they were members of the family of Aaron they could serve as priests only if they met certain qualifications. So there is a difference between merely being a priest and serving as a priest. That is important and instructive to us because this priesthood of the family of Aaron is a picture of the ministry that we have uniquely as believers in Jesus Christ. Every one of us who is born again, born into the family of our great high priest Jesus Christ, is by that fact inescapably a priest. But whether we can serve as a priest or not depends upon the qualifications in our life. Membership in the family is by birth; service in the family is by qualification.