And since it was not without an oath he was made priest:
All Commentaries on Hebrews 7:20 Go To Hebrews 7
George Leo Haydock
AD 1849
The old law was good in itself, being established by God, who does nothing in vain; but it was weak and imperfect, and the shadow and figure of that which was to come. It was preparatory to a more perfect dispensation under Jesus Christ, who, as our new high priest, was to finish by the gospel what Moses began by the law.