Hebrews 7:20

Since he was the one who under the law appointed priests but brought them to an end and declared another in their place, he was obliged to say that he appointed them without taking an oath, but in his case included an oath as well. …

364. – Having proved by the authority of the Psalmist that the priesthood of Christ is preferred to the Levitical and does away with it, the Apostle now proves the same thing by two other authorities: first, from the fact that he says, 'The Lord …

Here is another distinction of the new Priest from the ancient ones and of one covenant from the other. For the priesthood of Christ was promised not simply, but with an oath, so that the word of God would be fully believed, just as above, …

Not without an oath - “The apostle’s reasoning here is founded on this, that God never interposed his oath, except to show the certainty and immutability of the thing sworn. Thus he sware to Abraham, Gen 22:16-18, that in his seed all the nations of the earth should be blessed; and to the rebellious Israelites, Deu 1:34, Deu 1:35, that they should not enter into his rest; and to Moses, Deu 4:21, that he should not go into Canaan; and to David, Psa 89:4, that his seed should endure for ever, and his throne unto all generations.

THOSE Of you who read Scripture carefully will have noticed that the word, "better," is one of the key words of the Epistle to the Hebrews. You are constantly meeting with it. In the opening chapter we read that our Lord Jesus Christ is "made so much better than the angels, as He has by inheritance obtained a more excellent name than they." Look a little further and you are taught that He is better than Moses, inasmuch as Moses was faithful as a servant in the Lord's house, but Christ, as a Son over His own house.

THOSE Of you who read Scripture carefully will have noticed that the word, "better," is one of the key words of the Epistle to the Hebrews. You are constantly meeting with it. In the opening chapter we read that our Lord Jesus Christ is "made so much better than the angels, as He has by inheritance obtained a more excellent name than they." Look a little further and you are taught that He is better than Moses, inasmuch as Moses was faithful as a servant in the Lord's house, but Christ, as a Son over His own house. Further on we find our blessed Lord described as better than Aaron, while His blood is mentioned as speaking better things than that of Abel. And He is declared, in our text, to be the Surety of a better Testament, of which it is said that it is established upon better promises. It would be a very delightful subject to work out the betterness of Christ, of His blood, of His Covenant and to show that however good other things may be, they must all yield in excellence to Him. It is implied in the use of the word, "better," that the ordinances of the ceremonial Law were good, in their place, but Jesus is better than the best of all visible things—the eternal Christ is better than the best of all the temporal arrangements which God has made for the good of man. How much better what heart shall conceive? "If the ministration of condemnation is glory, much more does the ministration of righteousness exceed in glory. For if that which is done away with was glorious, much more that which remains is glorious." It behooves us, my dear Brothers and Sisters, to have a firmer faith than Old Testament saints because we see more clearly our ground of trust.

And inasmuch as not without an oath - In addition to every other consideration showing the superiority of Christ as a priest, there was the solemnity of the oath by which he was set apart to the office. The appointment of one to the office of priest by an oath, such as occurred in the case of Jesus, was much more solemn and important than where the office was received merely by descent.