Jeremiah 30:7King James Version (KJV)
7 Alas! for that day is great, so that none is like it: it is even the time of Jacob's trouble, but he shall be saved out of it.
Malachi 4:4-6King James Version (KJV)
4 Remember ye the law of Moses my servant, which I commanded unto him in Horeb for all Israel, with the statutes and judgments.
5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord:
6 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.