The answer
Malachi 3:1 is referring to St. John the Baptist. Malachi 4:5 could be referring to Elijah the prophet or St. John again, of whom it was said that he would come in the spirit, meaning with the same zeal, as Elijah the prophet. Another interpretation could also be alluding to the transfiguration of our Lord Jesus Christ, before whom the prophets Moses and Elijah appeared. A third possibility could be the reappearance of Elijah the prophet before the Second Coming of our Lord Jesus Christ.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)