The text of Psalm 110:4, to which the Hebrew writer here refers, contains a direct oath (an affirmation on an oath, this word is only used three times in the New Testament, all in the Hebrew letter). This is a Divine and unbreakable promise that the priesthood of Melchizedek will be eternal. No such promise was made to the priests under the Old Covenant.
This proves that this new covenant is a better one than the old covenant which tempted the readers of the epistle. No just better, but “so much better.”
Jesus is the guarantee that the new covenant is much better than the old. The Hebrew writer’s audience knew just how often death had taken the men who served as priests in the old covenant. In the case of men, “life is even a vapor that appears for a little time” (James 4:14).
But Jesus lives forever, and since this is so, there is never any change in the priesthood. The obvious result of this, as indicated in verse 25, is the inexhaustible ability of Christ to save as He always live to intercede.
