Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance
Hebrews 9:15 NIV
A covenant is a binding agreement between two parties. God reveals Himself progressively through the Bible as a covenant making, covenant keeping and covenant enabling God.
God initiated all of these covenants, which progressively revealed over the ages, a new aspect of His redemptive character and nature. Every covenant that God established made a way for those who honored Him, to know God and become beneficiaries of His promises in ever greater ways.
However, all of these covenants were temporary, until the new covenant was established through the shed blood of Jesus. This was the only covenant that dealt with sin and it’s penalty, once and for all.
“For the death that He died, He died to sin [ending its power and paying the sinner’s debt] once and for all” Romans 6:10 Amplified
God removed the old so that He could establish the new. A new and better covenant with new and better promises.
“But now Jesus, our High Priest, has been given a ministry that is far superior to the old priesthood, for He is the one who mediates for us a far better covenant with God, based on better promises” Hebrews 8:6 NLT
The writer of Hebrews adds; “Jesus has become the guarantor of a better covenant.” Hebrews 7:22 NIV
This means that God, not only established a new covenant, but He Himself became the guarantor of that covenant. A covenant of grace not law, guaranteed by God’s perfect sacrifice, not by whether we do right or wrong.
Jesus’ last words on the cross were. “It is finished.” The Greek word used for “finished” is “tetelestai.” This word was written on business documents or bills in new testament times to show that a bill had been paid in full.