Behold, the days come, says the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah:
All Commentaries on Jeremiah 31:31 Go To Jeremiah 31
Augustine of Hippo
AD 430
Because of the offense of the old Adam, which was by no means healed by the law that commanded and threatened, it is called the old covenant. The other is called the new covenant, because of the newness of the spirit that heals the new Adam of the fault of the old. Then consider what follows, and see in how clear a light the fact is placed, that people who have faith are unwilling to trust in themselves: “Because,” says he, “this is the covenant that I will make with the house of Israel; after those days, says the Lord, I will put my law in their inward parts and write it in their hearts.”