The LORD hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek.
The Lord hath sworn, and will not repent, Thou art a priest forever after the order of Melchizedek - who in Zion ("Salem," Hebrews 7:1) united the priestly with the kingly office. David could bring judgment on his people, but could not effect an atonement and reconciliation (2 Samuel 24:17). He was not a priest. The Son of David, our ever continuing Priest (as contrasted with the Aaronic priests, ever needing, through death, renewal) puts away the sin of His people (God's hand having been against Him instead of against us), so that they wear the holy garment of His perfectly imputed righteousness, and shall be finally sanctified wholly. God Himself "swears" irrevocably (Numbers 23:19) for our assurance, that this everlasting Priest is of His own appointment. The final victory of Messiah's people over the world and Satan is therefore certain. The oath of God did not accompany the Aaronic priesthood, as it does our Melchizedek-like Priest, who "is made not after the law of a carnal commandment, but after the power of an endless life" (see notes, Hebrews 7:1-3; Hebrews 7:16-28). "After the order of Melchizedek" is explained, Hebrews 7:15, "after the similitude of Melchizedek." The oath of covenant on the part of the Father to the Son is for the comfort of Messiah's people. Uzziah's punishment for his usurpation of the functions of priest shows that David cannot be the King-Priest here described (2 Chronicles 26:16-21). The extraordinary oath of God shows that the King-Priesthood here is something unparalleled. David died, but this Melchizedek-like Priest lives forever. Zechariah 6:9-15, especially 13, similarly describes Messiah - "He shall sit and rule upon His throne, and He shall be a Priest upon His throne."