The people of God have always had hope of salvation. From the beginning, it has been promised that the serpent would be destroyed (Gen. 3:14–15). But under the old covenant, this hope was only a shadow. The Levitical system provided a temporary solution to the problem of sin by offering reconciliation with God. But this system could not eliminate sin; it could not perfect anyone (Heb. 7:11).
The hope of salvation offered under the new covenant is far better. Under the new covenant we have a permanent priest, a priest after the order of Melchizedek. Jesus, the Lion of the tribe of Judah, has been ordained as our eternal priest because of His indestructible life (7:16). Since this has been done, the former imperfection of the Levitical priesthood has been set aside in favor of the perfection guaranteed by Christ (v. 17). Christ’s priesthood guarantees that we can draw near to Him (v. 19). Unlike most of the old covenant saints, we can leave the temple courts and draw near to God in the holy place (10:19–22).
The extended discussion we have thus far seen concerning the Melchizedekian priesthood of Christ tells us that this idea may have not been well known by the original audience of Hebrews. We should not necessarily fault them too much for this as it is not a theme emphasized during the earthly ministry of Jesus. We do see hints at His priestly office (for example, Matt. 20:28), but the Holy Spirit did not make full disclosure of this fact until after the ascension of Christ. As a result, many would have doubted this teaching and would need confirmation that Jesus truly was their High Priest.
The author emphasizes the surety of Christ’s eternal priesthood by quoting again from Psalm 110. In Hebrews 7:20 we are reminded that God never swore that Aaron’s priesthood would be eternal. Rather, this permanence belongs to the priest in the order of Melchizedek. This permanence, as verse 21 tells us, is guaranteed by God’s oath. This is most notable. As we have discussed, some of the promises of God are implicitly conditional and may or may not come to pass depending on the response of the people (Jer. 18:5–10). But this is not so when God makes an oath. God’s oaths signify that He will absolutely do what he has sworn. He has sworn that Christ is our eternal High Priest and there is absolutely nothing that will ever change that.
God has sworn that Christ will most certainly be High Priest forever. His covenant will never pass away. We never have to fear if we trust in Christ alone because He will make us holy and He will vindicate us in the end. Remember that we can stand boldly in the face of danger because we belong to a kingdom that will never end.