Malachi 3:1-6a:

Well, pay attention!
I am sending my Messenger
to prepare the way for me;
the One you seek will suddenly come to the Temple, 
the Messenger of the Covenant whom you long for will come, 
says YHWH Omnipotent.  
But who can endure the day of that Coming? 
Who can stand firm when that One appears?
That day will be like a smelter’s fire, 
a launderer’s soap.  
The One will preside as refiner and purifier, 
purifying the Children of Levi, 
refining them like gold and silver—
then they will once again
make offerings to YHWH in righteousness.  
Then the offerings of Judah and Jerusalem
will be pleasing to YHWH as they were in former days, 
in years long past.  
I will appear before you in court, 
to testify against the sorcerers, adulterers, and perjurers, 
against those who cheat the hired laborers of their wages, 
and oppress the widow and the orphan, 
who rob foreigners of their rights
and have no respect for me, says YHWH Omnipotent.  
No—I, YHWH, do not change.