A new covenant is promised, which would be different from the Sinai covenant (31:31-32), for although the Lord was gracious to his people in liberating them from Egypt, Israel did not abide by the stipulations of the covenant. By way of contrast, "it will not be possible to breach the new covenant." The new covenant is of a different character, for now the Lord will write his law on the hearts of his people so that they will obey him (31:33). Israel would experience what it means for Yahweh to be their God and to live as his people. "The new covenant. . . is a way of solving the basic problem identified in earlier parts of the book. . . namely, the failure of the covenant people to be faithful."
Every member of the covenant people would know the Lord (31:34). Every member of the covenant family would have the law written on their hearts. . ." pg. 361,362 "The King In His Beauty: A Biblical Theology of the Old and New Testament" by Thomas R. Schreiner