Hebrews 7:18-22 (HCSB)
So the previous command is annulled because it was weak and unprofitable (for the law perfected nothing), but a better hope is introduced, through which we draw near to God.
None of this happened without an oath. For others became priests without an oath, but He became a priest with an oath made by the One who said to Him:
The Lord has sworn,
and He will not change His mind,
You are a priest forever.
So Jesus has also become the guarantee of a better covenant.
The New Covenant is not simply a theological or philosophical construct. It is a clearly identified reality, both in Jesus teaching during the Last Supper (Luke 22: 20), and in the teaching the epistles.
The key reason for the setting aside of the Old Covenant is specifically because it was weak, providing atonement, but completely unable to provide transformation or renewal of the soul into the image of God. People could draw near to the place where God’s presence was manifested, but true unity with Him was not possible due to the mismatch in character between himself and sin-twisted humanity.
The writer of Hebrews also points out that, unlike a purely human high priest who entered into a role under the Old Covenant without benefit of a divine oath, Jesus became the author of the New Covenant as well as its first and only High Priest with an oath from God.
That divine oath ensured the validity of the New Covenant. It also ensured that the New Covenant would never change or become distorted, or even nullified, by the whims of some future high priest who decides to remake it according to his own desires and interpretation. Since Jesus is and will be the only High Priest of the New Covenant, and since He, as God in the flesh, never changes, the New Covenant, ratified by His blood, is permanent and unchangeable.
Father, we live in times right now where so little seems stable, let alone unchangeable. How good it is to know that Your covenant that is contained and exposited in our Scriptures is the same as that which Jesus founded, the same as that under which the early Church flourished, and is one that we can confidently pass on to our children and grandchildren as Your final word on salvation, sanctification, transformation, and eternal life. Thank You for a solid foundation on which to build our lives in uncertain times. Amen.