The book of the prophet Malachi is a small book, but so full of revelation about the Lord and His Character.
We can see the Lord speak about the right Fatherhood in His face and the proper Sonship attitude we should have as His children, as well as holiness for the priests (chapter 1), faithfulness and judgment (chapter 2) and even ministering to the Lord with tithes, offerings and the right heart composition on our part (chapter 3).
Now I would like to stress out several images of the Lord Jesus here, which portray Him as the Messenger of the covenant, the promised Messiah from the Lord, Who would come and be the fulfilment of the desire of all who have waited for Him, and at the same time, the carrier of judgment for the ones who did not expect Him.
Also, we can see Jesus here in chapter 3, as the Refiner, Purifier and Cleanser of God's Temple, God's Priests and the offerings of the people. We can clearly see Jesus do that in New Testament times too, when He entered the temple in Jerusalem and cleansed it, on several occasions. Let's see the verses from Malachi that speak of all these things, because this portion of Scripture speaks very well of itself and does not need interpretation really:
"See, I will send my messenger, who will prepare the way before me. Then suddenly the Lord you are seeking will come to his temple; the messenger of the covenant, whom you desire, will come, says the Lord Almighty. But who can endure the day of his coming? Who can stand when he appears? For he will be like a refiner's fire or a launderer's soap. He will sit as a refiner and purifier of silver; he will purify the Levites and refine them like gold and silver. Then the Lord will have men who will bring offerings in righteousness, and the offerings of Judah and Jerusalem will be acceptable to the Lord, as in days gone by, as in former years. "So I will come near to you for judgment. I will be quick to testify against sorcerers, adulterers and perjurers, against those who defraud laborers of their wages, who oppress the widows and the fatherless, and deprive aliens of justice, but do not fear me," says the Lord Almighty." (3:1-5)