Of temples

"And the Lord, whom ye seek, shall suddenly come to his temple ... and he shall sit as a refiner and purifier of silver, and he shall purify the sons of Levi ..." -- Malachi 3:1,3.

Please tell me, if temples are part of the old covenant, done away with, and the Mormons are wrong to build them, then how will this Millennial prophecy be fulfilled? To where will the Lord suddenly come?

The Lord repeated a portion of this prophecy in December, 1830, in direct first-person revelation to the Prophet Joseph Smith, just a few months after the Church of Jesus Christ was restored on the earth.