For this reason, Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance—now that he has died as a ransom to set them free from the sins committed under the first covenant.

Hebrews 9:15 (NIV)

 

As our Mediator of the New Covenant, Jesus was uniquely qualified to act on the behalf of God and us because He is the only one who possesses both divine and human nature. His ransom sacrifice on the Cross permanently freed us from the penalty of sin that the Old Covenant could not remove, as well as secured for us the promised eternal inheritance of the New Covenant. His finished work gives us the perfect assurance and security of our salvation.

The Old Covenant was based on the Law. It was a covenant of works which no one could obey God by their own power due to the sinfulness of their hearts. The New Covenant is based on faith in Christ. It is a covenant of grace that erased sin and guarantees salvation through the perfect work of Jesus.

The New Covenant is integrally connected to the new priesthood of Jesus after “the order of the Melchizedek.”

According to the writer of Hebrews, when there is a change of priesthood, the law must be changed also (Hebrews 7:12). The law of the Old Covenant, which became the ministry of "death" and "condemnation" (2 Corinthians 3:6,7,9), was written on stone. The new law of life and liberty of the New Covenant is implanted on the heart since the Holy Spirit lives within us. God in Christ has given us a new heart and spirit to be faithful and fruitful through all life’s circumstances. This is why we describe the New Covenant as "a better covenant, established on better promises" (Hebrews 8:6-8).