"Look! I'm sending my messenger on ahead to clear the way for me. Suddenly, out of the blue, the Leader you've been looking for will enter his Temple - yes, the Messenger of the Covenant, the one you've been waiting for. Look! He's on his way!" A Message from the mouth of God-of-the-Angel-Armies.
But who will be able to stand up to that coming? Who can survive his appearance? He'll be like white-hot fire from the smelter's furnace. He'll be like the strongest lye soap at the laundry.
He'll take his place as a refiner of silver, as a cleanser of dirty clothes. He'll scrub the Levite priests clean, refine them like gold and silver, until they're fit for God, fit to present offerings of righteousness.
Then, and only then, will Judah and Jerusalem be fit and pleasing to God, as they used to be in the years long ago.