Charles Ellicott Commentary Hebrews 7:28

"For the law appointeth men high priests, having infirmity; but the word of the oath, which was after the law, [appointeth] a Son, perfected for evermore." — Hebrews 7:28 (ASV)

For the law makes men high priests who have infirmity...—Better, For the Law appoints men high priests, (men) having infirmity; but the word of the oath, which was after the Law, appoints a Son, who has been perfected forever.

On “the word of the oath,” see Hebrews 7:20-21. Coming “after the Law,” it revoked the commandment (Hebrews 7:18) and was not revoked by it.

(Regarding “A Son,” see Hebrews 1:3 and Hebrews 5:8. For “Perfected,” see Hebrews 2:10 and Hebrews 5:10.) We are not to understand that Jesus was first “perfected” and then appointed as High Priest: this would contradict what has just been taught (Hebrews 7:27), for it was as High Priest that He offered the sacrifice of Himself.

In these closing words are united the two cardinal predictions of Psalms 2 and Psalms 110 : “You are My Son,” “You are a Priest forever.”