But who may abide the day of his coming and who shall stand when he appeareth? And this is the cry that goes up from the final pages of the Old Testament (Mal 3:2). And the Lord himself gives the answer:
See, I will send you the prophet Elijah before that great and dreadful day of the Lord comes. He will turn the hearts of the fathers to their children, and the hearts of the children to their fathers; lest I come and strike the land with doom! (Mal 4:5-6)
And thus with these words the Old Testament ends.