Curses of the covenant

“But they did not listen or pay attention; instead they followed the stubbornness of their evil hearts. So I brought on them all the curses of the covenant I commanded them to follow but that they did not keep.” Jeremiah 11:8
Here God tells Jeremiah His reasons for the trouble that Israel was experiencing. They were under the Mosaic covenant, by which if the nation Israel obeyed God and kept the Law that He gave them, He would bless them. But if they turned away from God and disobeyed the Law, they would be cursed.
In Deuteronomy 28 are given the blessings for obedience (v1-14) and the curses for disobedience (v15-68). That is, 14 verses of blessings, but 54 verses of curses. This is not because God enjoys cursing people. It is because He knew that they would tend to fall into disobedience, and so He emphasises what would happen in that case, so they would be dissuaded from doing it.
If we are in Christ, we are no longer under the Mosaic covenant. We are under the new covenant, as promised in Jer. 31:31-34 (see also Luke 22:20, 2 Cor. 3:6, Heb. 9:15). The new covenant does not include curses, because it involves the Holy Spirit indwelling our hearts. If we are following our evil hearts, we have not been born again and are therefore not part of the new covenant.