The Messenger of the Lord
17 You have wearied the Lord with your words. But you say, “How have we wearied him?” By saying, “Everyone who does evil is good in the sight of the Lord, and he delights in them.” Or by asking, “Where is the God of justice?”
3:1 “Behold, I send my messenger, and he will prepare the way before me. And the Lord whom you seek will suddenly come to his temple; and the messenger of the covenant in whom you delight, behold, he is coming, says the Lord of hosts. 2 But who can endure the day of his coming, and who can stand when he appears? For he is like a refiner's fire and like fullers' soap. 3 He will sit as a refiner and purifier of silver, and he will purify the sons of Levi and refine them like gold and silver, and they will bring offerings in righteousness to the Lord. 4 Then the offering of Judah and Jerusalem will be pleasing to the Lord as in the days of old and as in former years.
5 “Then I will draw near to you for judgment. I will be a swift witness against the sorcerers, against the adulterers, against those who swear falsely, against those who oppress the hired worker in his wages, the widow and the fatherless, against those who thrust aside the sojourner, and do not fear me, says the Lord of hosts. (ESV)