"The time is coming - it is YAHWEH who speaks - when I will forge a new covenant with the people of Israel and the people of Judah. It will not be like the one I made with their fathers when I took them by the hand and led them out of Egypt. For they broke MY covenant although I was their LORD.
This is the covenant I shall make with Israel after that time: I will put MY Law within them and write it on their hearts; I will be their GOD and they will be MY people.
And they will not have to teach each other, neighbor or brother, saying: 'Know the LORD,' because they will all know ME, from the greatest to the lowliest, for I will forgive their wrongdoing and no longer remember their sin." - Jeremiah 31:31-34
(Here we must underscore 31:31-34 where Jeremiah delivers his most famous prophecy. During the bitter days which the Jewish people are experiencing, GOD reveals, and Jeremiah announces the New and eternal Covenant between GOD and HIS people.
I will make a new covenant. This is likeable to escape saying that the Sinai Covenant which made Israel GOD's people, had become obsolete or insufficient. GOD had bound HIMSELF to a family [Abraham's] which became a people under Moses' leadership. And apparently HIS promises were more for the community than for individuals.
The expression the prophet uses, "a new covenant" does not mean that GOD is forsaking HIS former promises to Israel. It clearly illustrates the characteristic of the covenant which GOD wants to establish between HIM and humanity through Israel. This novelty is that of love, because true love is always fresh and new. Although the people of GOD had broken the covenant, GOD who is always faithful, will respond by a gift, through HIS son, born of Mary.
They broke MY covenant. Actually, this covenant between YAHWEH and Israel on Sinai had failed, through Israel's fault, not YAHWEH's. But it is not a matter of renewing it as Joshua, Samuel, Hezekiah and Josiah had done so many times. Nor is it a matter of making another one like it, since this old covenant had already proven its weakness: people are sinful and unable to escape from their sins. Moreover, no laws, or human solidarity, or any form of education can bring GOD's grace to a nation or a collectivity and preserve them in the faith. Only a personal accepting of the divine Truth makes one a true believer. The true people of GOD cannot be confused with any people or human community: only those who are reborn will become part of GOD's people.
I will put MY Law in their hearts. Now, Jeremiah knows the secret of the New Covenant. For he is aware of the change which occurred in him when YAHWEH made him a prophet. Then, he discovered an intimate relationship with GOD which is entirely different from a religion of mere practices.
I will make another covenant with Israel. Jeremiah predicts the day when YAHWEH will reveal HIMSELF to all believers as HE had done with HIS great prophets. The law will be in their hearts and the hand of GOD will keep them on the right path, as was the case with Jeremiah when he doubted.
I will forgive their sins. A New Covenant will be achieved through the death of CHRIST on the cross for the forgiveness of sins. In celebrating the Last Supper, JESUS says: "This cup is the New Covenant in MY blood" [Luke 22:20]. The author of the Letter to the Hebrews will develop the meaning of the New Covenant [see Hebrew 8:8 and 10:16]
The Gospel of John will also clarify the meaning of they will all know ME: in the Christian faith, not everyone receives personal revelations, but everyone is guided by the FATHER to CHRIST in whom are found all the treasures of knowledge and wisdom.
Perhaps Jeremiah himself had not seen all the consequences of this revelation, but it certainly throws a decisive light on the history of the people of Israel. We understand that GOD's teaching, HIS way of leading and instructing HIS people through events was a pedagogy, leading to a definitive truth to be given through CHRIST and through the gift of the Spirit. It is understandable that JESUS and HIS apostles so often recalled the message of the prophets to justify the revolution of the Gospel and the birth of a Church rooted in the Jewish people but now independent of its national history.)