Jeremiah 31:33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, And write it in their hearts; And will be their God, And they shall be my people. 34 And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: For they shall all know me, From the least of them unto the greatest of them, saith the LORD: For I will forgive their iniquity, And I will remember their sin no more.
The promise, covenant, is that one day God is going to put His law in the hearts of the people of Israel. It will be written there. They will no longer need people to teach the law. They will no longer need evangelists. They will all know Him. He will forgive their iniquity. He will have put their sin behind them.
The millennial kingdom is coming where God will use Israel in great ways. Things will happen then that we simply do not understand. God is going to do things with Israel we have never seen Him do with the church. What a promise He gave them through His man, Jeremiah.