The Lord declares that he will send his messenger to prepare the way before him. Suddenly the Lord whom they seek will come to his temple, the messenger of the covenant whom they desire, and no one will be able to endure the day of his coming. He will be like a refiner's fire and like fullers' soap: he will sit as a refiner of silver and purify the sons of Levi so that they present offerings in righteousness. Then the offering of Judah and Jerusalem will be pleasing to the Lord, as in the days of old (vv. 1-4).
The Lord will also draw near for judgment and will be a swift witness against sorcerers, adulterers, those who swear falsely, those who cheat the hired worker, the widow and the orphan, and those who turn aside the foreigner. God affirms that he does not change, and that is why the sons of Jacob have not been destroyed. He calls them to return to him, and they ask how they are to return. God answers with an accusation: they have robbed him in tithes and contributions, and so they are under a curse. He invites them to bring the full tithe into the storehouse so that there may be food in his house, to test him, and see whether he will not open the windows of heaven and pour out blessing until there is more than enough. He will also rebuke the devourer so that it does not destroy their crops, and all nations will call them blessed (vv. 5-12).
The Lord now quotes the harsh words some have spoken: that it is vain to serve God, and that the arrogant are happy. But those who feared the Lord spoke with one another, and the Lord listened and wrote a book of remembrance. They will be his, a treasured possession, on the day he acts, and he will spare them as a father spares the son who serves him. Then the difference between the righteous and the wicked will be seen again (vv. 13-18).