OT § 184

Thus says the Lord Almighty: See, I am sending my Angel, my messenger, before your face, who will prepare your way before you. And the Lord whom you seek will come to his temple. And who will endure the day of his entrance? And who will withstand at his appearing? Because he will enter like fire in a smelting furnace and like the lye of launderers. And he will come to you in judgement; and he will be a swift witness against the wicked and against adulteresses and against those swear falsely in his name and those who do not fear him, says the Lord Almighty. Because I am the Lord your God, and I have not changed and you, children of Jacob, have perverted the laws and not kept them. Therefore turn back to me and I will turn back to you, says the Lord Almighty. And all the nations will call you blessed and you will know that I am the Lord who discern between just and lawless on the day on which I make a peculiar possession of those who love me. Know then and remember the law of Moses my servant, as I gave him commandment on Horeb, to all Israel ordinances and judgements. And see, I will send you Elias the Thesbite, before the great and manifest day of the Lord comes; he will turn again the heart of father to son and of a man to his neighbour, lest when I come I smite the earth grievously, says the Lord Almighty, God the Holy One of Israel.