My wife has had both of her knees replaced. She didn’t do it because she wanted to try out something new, like a new pair of shoes; the replacement was need driven. We replace the old with the new when the old no longer works as it was designed to. We get that new thing (car, appliance, knee) hoping that it will work better than the old and will hopefully never need to be replaced again!
Have you experienced something like this in your faith journey? Possibly you discovered that what you were holding onto was not working. Maybe you were struck by the fact that Jesus came bringing the new covenant to replace the old covenant because the old was inadequate. The new was not a mere upgrade of the old, like a knee replacement, but it was much more. The new covenant is fundamentally better than the old because it permanently satisfied the Law.
Paul reveals the differences between the old and new covenants in 2 Corinthians 3 saying, “[God] has enabled us to be ministers of his new covenant. This is a covenant not of written laws, but of the Spirit. The old written covenant ends in death; but under the new covenant, the Spirit gives life.” (3:6)
Paul makes two important distinctions here. First, the old covenant was written on stone. This refers to the Ten Commandments written on the stone tablets. Paul says that the new covenant is different; it is written on our hearts by the Holy Spirit. Hebrews 10 notes, “This is the new covenant I will make with my people on that day, says the LORD: I will put my laws in their hearts, and I will write them on their minds.” (10:16)
Second, the old written covenant ends in death where the new gives life. In Romans Paul testifies that, “For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.” (6:23) Death refers not only to physical death, but more importantly, to the eternal death, separation from God, that is the result of our sins, “But your iniquities are separating you from your God, and your sins have hidden his face from you so that he does not listen.” (Isaiah 59:2). The consequence of sin is eternal separation from God, but Christ came to bring forgiveness that gives eternal life.
The promise of the new covenant is found in the prophet Jeremiah’s words, ““But this is the new covenant I will make with the people of Israel after those days,” says the LORD. “I will put my instructions deep within them, and I will write them on their hearts. I will be their God, and they will be my people. And they will not need to teach their neighbors, nor will they need to teach their relatives, saying, ‘You should know the LORD.’ For everyone, from the least to the greatest, will know me already,” says the LORD. “And I will forgive their wickedness, and I will never again remember their sins.” (Jeremiah 31:33–34)
Jeremiah reveals three things that the new covenant brings. First, God’s law will become internally known. Ezekiel puts it this way, "[God] will give you a new heart with new and right desires, and I will put a new spirit in you. I will take out your stony heart of sin and give you a new, obedient heart. And I will put my Spirit in you so you will obey my laws and do whatever I command" (Ezekiel 36:26-27).
Second, Jeremiah says that the new covenant will give us direct knowledge of God. No longer will we need a priest or mediator to intercede for us. Jeremiah promise that with the new covenant God will dwell within us and that we’ll personally know Him.
Finally, thru the new covenant we will know that our sins are forgiven. Jeremiah says, “[God] will forgive their wickedness and will remember their sins no more." Isn’t that what we want? Isn’t that what we need? As Hebrews 10 promises, ““I will never again remember their sins and lawless deeds.” And when sins have been forgiven, there is no need to offer any more sacrifices.” (17–18)
Look again to the verse from Jeremiah; notice the six “I will” statements. The new covenant comes as the result of God’s work not ours. This allows the Christian to rejoice knowing their hope is sure because it’s based in what the Lord has done rather than in what we might do.