Malachi 4:4-6

Remember the law of Moses my servant, which I commanded unto him in Horeb for all Israel, the statutes and ordinances. Behold, I send unto you Elijah the prophet, before the coming of the great and terrible day of Jehovah. And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.