1“For behold, the day comes, burning like a furnace, when all the proud and all who work wickedness will be stubble. The day that comes will burn them up,” says Yahweh of Armies, “so that it will leave them neither root nor branch. 2But to you who fear my name shall the sun of righteousness arise with healing in its wings. You will go out and leap like calves of the stall. 3You shall tread down the wicked; for they will be ashes under the soles of your feet in the day that I make,” says Yahweh of Armies.
4“Remember the law of Moses my servant, which I commanded to him in Horeb for all Israel, even statutes and ordinances.
5Behold, I will send you Elijah the prophet before the great and terrible day of Yahweh comes. 6He will turn the hearts of the fathers to the children and the hearts of the children to their fathers, lest I come and strike the earth with a curse.”
The Greek word for "repent" is metanoia (μετανοια), a combination of two words. "Meta" refers to a change, or after, and "noia" of the mind. It speaks not to "remorse," sometimes thought to be its sense. Rather, the call of John is to change their minds, to think differently. This was to be done in view of the coming kingdom of the Messiah. There is a difference among biblical interpreters as to whether the kingdom of heaven and the kingdom of God are synonyms. Whichever view one takes, it is clear that this begins with the coming of Jesus. It is clear that this kingdom was first offered to the Jewish people and that there would be a judgment of those who rejected Him (3:12), a view repeated by the Old Testament several times (Isa 4:4, 5; 5:15, 16; 42:1; Jer 33:14-16; Ezek 20:33-38; Dan 7:26, 27; Joel 1:14, 15; 3:12-17; Zeph 1:2-18; 3:8-13; Zech 13:2, 9; Mal 3:1-5; 4:1-6).