The words 'covenant' and 'testament' are little-used words in modern English. But the two major divisions of our Bible are called "Old Testament" and "New Testament." We should know why!

God made several covenants with various people and groups in the Old Testament. Some of those were unconditional promises and some depended on participation of the people. Humanity proved incapable of keeping any covenant with God, and through the prophet Jeremiah God foretold he would make a New Covenant to replace all the old broken ones. That prophecy was fulfilled by Jesus Christ in the Lord's Supper, which is the new covenant in Christ's blood.

• The old covenant foreshadowed the new covenant (Hebrews 10:1)
• Jesus established this new covenant (Luke 22:20)
• The new covenant is superior to the old covenant (Hebrews 8:6)
• God’s new covenant brings life (2 Corinthians 3:6)

('Covenant' and 'testament' are the same word in the biblical languages. But in English they have a subtle distinction. For us, 'covenant' is usually understood to be two-sided with a penalty for breaking it, while 'testament' is a one-sided promise without penalty.)

Here is a summary of this theme from The Bible Project. You can watch their short, 6-minute video ~HERE.~

There are several ways in which we have a relationship with God, some of which you have probably heard about many times before. God is depicted as our friend, our teacher, and our master. Yet there is another facet of our relationship with God that doesn't get quite as much attention, and that is God as our partner.

In the very beginning of the Bible, this is the relationship we see. God creates man as a partner to help him spread more goodness throughout the world. Unfortunately, we, as human beings, didn't live up to our end of the deal. It is this broken partnership with God that is the reason we are stuck with the fallen and corrupted world in which we live. Thankfully, the rest of the Bible describes God's efforts to repair this broken partnership.

The first step God takes in repairing this partnership is to select a small group of people and make a new partnership with them called a "covenant." In this covenant, God makes promises to these people and asks them to fulfill certain commitments.

In total, there are four Old Testament covenants—one with Noah, one with Abraham, one with the Israelites, and one with King David. All these covenants serve the purpose of creating a new partnership into which God can eventually invite all humankind. Unfortunately, Israel eventually breaks these covenants with God.

Nevertheless, throughout the Old Testament, prophets talked about a day when God would once again create a new covenant, one that would completely restore all the broken covenants that came before it. This new covenant was fulfilled by God's Son, Jesus Christ.

We're told in the Bible Christ is a descendant of Abraham, allowing him to fulfill the covenant God had with Abraham and his family. We're also told Christ is the faithful Israelite who is able to truly obey the law, and Christ is the king from the line of David. This allows Christ to fulfill God's covenant with these people as well, thus restoring all the covenants in the Bible.

In this way, Christ himself is the New Testament covenant—a covenant that cannot fail and cannot be broken. Christ invited people to follow Him and join Him in a new partnership with God. Despite our failures, we are able to enter into this new covenant thanks to the fact Christ Himself was able to perfectly fulfill His commitment to God. Through His perfect keeping of the new covenant, we too are now able to enjoy a renewed partnership with God.

At the end of the Bible, we see John describing a new and perfect partnership with God where all the saved work with Him to once again spread goodness and perfection throughout the world. Thanks to the fulfillment of the new covenant through Jesus Christ, God's initial plan for mankind is made complete again.