Matthew Poole and continuators on Hebrews 10:14

14 For by one offering he hath perfected for ever them that are sanctified.

For, here gives the Reason of the precedent Effect, and it is opposed to the Reason of the legal Offerings defect; their Sacrifices multiplied could not perfect Sinners, but this one doth it fully; For by one, &c.

Christ, God-Man, the Gospel-High-Priest by the one Offering of himself a Sacrifice for Sin to God his Father, and once performed by him, hath secured Perfection of Justification, Sanctification, and Blessedness, perpetually to be continued, whereby the Persons interested in it, are qualified and consecrated to be Priests to God and his Father (as the Aaronical Priests were by the Sacrifice of the Ram of Consecration, Exod. 29.22, 24.) to serve in their proportion here, but especially after the completion of it by their Resurrection, they shall perfectly serve him before his Throne in the Holy of Holiest for ever, 1 Pet. 2.9. Rev. 1.6. and 5.10. and 20.6.

The renewed Souls by the Holy Ghost, such whose Consciences he hath sprinkled with the Blood of Jesus, and by it freed them from the Guilt of Sin and its Punishment, and whose Natures he regenerates and sanctifieth, freeing them from their evil Habits, and making them inherently Holiness unto the Lord, Psal. 110.3. 1 Cor. 6.11.