And inasmuch as not without an oath he was made priest:

And by how much it was not without the swearing of an oath;

And inasmuch as it is not apart from oath, (for those indeed apart from oath are become priests,

And since it was not without an oath being taken -

Moreover, it is not without an oath. For certainly, the others were made priests without an oath.

Then again, the appointment of this new priest was ratified by an oath, which is not so with the Levitical priests,

Atque hoc potiorem, quod non absque jurejurando res acta sit: nam illi quidem citra jusjurandum sacerdotes facti sunt:

And inasmuch as not without an oath, etc. Here is another argument, why the Law ought to give place to the Gospel; for God has set Christ's priesthood above that of Aaron, since in honor to the former he was pleased to make an oath. For when he appointed the ancient priests, he introduced no oath; but it is said of Christ, the Lord swore; which was doubtless done for the sake of honoring him. We see the end for which he again quotes the Psalmist, even that we may know, that more honor through God's oath was given to Christ than to any others. But we must bear in mind this truth, that a priest is made that he may be the surety of a covenant. The Apostle hence concludes, that the covenant which God has made by Christ with us, is far more excellent than the old covenant of which Moses was the interpreter.

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.

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, Genesis 22:16-18, that in his seed all the nations of the earth should be blessed; and to the rebellious Israelites, Deuteronomy 1:34, Deuteronomy 1:35, that they should not enter into his rest; and to Moses, Deuteronomy 4:21, that he should not go into Canaan; and to David, Psalm 89:4, that his seed should endure for ever, and his throne unto all generations. Wherefore, since Christ was made a priest, not without an oath that he should be a priest for ever, after the similitude of Melchisedec, that circumstance showed God's immutable resolution never to change or abolish his priesthood, nor to change or abolish the covenant which was established on his priesthood; whereas the Levitical priesthood and the law of Moses, being established without an oath, were thereby declared to be changeable at God's pleasure." This judicious note is from Dr. Macknight.

(10) And inasmuch as not without an oath [he was made priest]:
(10) Another argument, by which he proves that the priesthood of Christ is better than the priesthood of Levi, because his was established with an oath, but theirs was not so.

And inasmuch as not without an oath,.... Our version supplies as follows,
he was made priest; which well agrees with what is said in the next verse; the Syriac version renders it, "and which he confirmed to us by an oath"; that is, the better hope, Christ and his priesthood, said to be brought in, and by which men draw nigh to God; this is established by the oath of God himself referring to Psalm 110:4 afterwards cited in proof of it.

Another proof of the superiority of Christ's Melchisedec-like priesthood; the oath of God gave a solemn weight to it which was not in the law-priesthood, which was not so confirmed.
he was made priest--rather supply from Hebrews 7:22, which completes the sentence begun in this verse, Hebrews 7:21 being a parenthesis, "inasmuch as not without an oath He was made surety of the testament (for, &c.), of so much better a testament hath Jesus been made the surety."

And - The greater solemnity wherewith he was made priest, farther proves the superior excellency of his priesthood.