EWTN Catholic Q&A
Jesus being the first priest to serve a mass
Question from Andrew on 11-03-2012:

How could Jesus be a Priest when He was still in the old covenant and the only ones who were allowed to be priests were from the tribe of Levites and Jesus was from the tribe of Juda. Jesus would not break is own law

Answer by Fr. John Echert on 11-06-2012:

The levitical priesthood of the Old Covenant was a pre-figurement of the New Covenant priesthood of Jesus Christ. It was never intended to be permanent and so God did not break his own law. This is best presented in the Epistle to the Hebrews, which has as its theme the replacement of the levitical priesthood with the High Priesthood of Christ. Give it a good read...it is worth the time.

Thanks, Andrew

Father Echert