This pericope opens with a reminder about God’s future day of judgment that is coming. The Lord declares, “For behold, the day is coming, burning like a furnace; and all the arrogant and every evildoer will be chaff; and the day that is coming will set them ablaze… so that it will leave them neither root nor branch” (Mal 4:1). This time of judgment is commonly called “the day of the Lord”, a phrase that appears eighteen times in the Old Testament (Isa 13:6, 9; 58:13; Ezek 13:5; 30:3; Joel 1:15; 2:1, 11, 31; 3:14; Amos 5:18, 20; Obad 1:15; Zep 1:7, 14; Mal 4:5) and five times in the New Testament (Acts 2:20; 1 Cor 5:5; 1 Thess 5:2; 2 Thess 2:2; 2 Pet 3:7-14). The “day of the Lord” refers to when God will judge the wicked and vindicate the righteous. From Scripture we can say with certainty that the “day of the Lord” follows the first coming of Christ, (Mal. 4:5), will come upon the entire world (Joel 2:1-11; 30-31; 3:12-15; Isa 13:6-11; Ezek 30:2-4; Obad 1:15), will be inescapable (Amos 5:18-20), is a day of wrath and destruction (Zep 1:14-18), will come unannounced (1 Thess 5:1-2; 2 Pet 3:10), and will follow the coming of the Antichrist (2 Thess 2:1-4). The church will not experience this time of God’s judgment, for we are waiting for the return of Christ from heaven, “who rescues us from the wrath to come” (1 Thess 1:10; cf. 5:9). The period refers to the seven-year Tribulation (Rev chapters 6-18) and will end with the Battle of Armageddon (Rev 19:11-21), at which time Christ will establish His millennial kingdom on earth (Rev 20:1-6).
The end of the Tribulation and coming millennial kingdom seems to be in view of Malachi in which the Lord declares, “But for you who fear My name, the sun of righteousness will rise with healing in its wings; and you will go forth and skip about like calves from the stall. You will tread down the wicked, for they will be ashes under the soles of your feet on the day which I am preparing” (Mal 4:2-3). “In the kingdom, righteousness will pervade like the sun. Healing in its wings (or rays) refers to the restorative powers of righteousness, which are like the healthful rays of the sun. God’s people will be spiritually restored and renewed.” With this future time of judgment and blessing certainly coming, Malachi’s generation should have been more mindful about how they lived before the Lord, adhering to the Mosaic Law, which was the standard for right-living for the nation. God had already confronted them concerning sacrifices (Mal 1:7-14), idolatry (Mal 2:10-11), and not giving tithes (Mal 3:8-9), and finally exhorts them to “Remember the law of Moses My servant, even the statutes and ordinances which I commanded him in Horeb for all Israel” (Mal 4:4).
Finally, God gives a prophecy concerning the future coming day of judgment. He declares, “Behold, I am going to send you Elijah the prophet before the coming of the great and terrible day of the LORD. He will restore the hearts of the fathers to their children and the hearts of the children to their fathers, so that I will not come and smite the land with a curse” (Mal 4:5-6). The Gospel of Luke reveals John the Baptist had an Elijah-like ministry in that he came “in the spirit and power of Elijah” (Luke 1:17). If Israel had accepted Jesus as the Messiah and His offer of the kingdom, then John the Baptist would have fulfilled this prophecy (Matt 11:7-14).
- "The Lord promised to send His people Elijah the prophet before the great and terrible day of the Lord arrived. An angel later told John the Baptist’s parents that their son would minister in the spirit and power of Elijah (Luke 1:17). Yet John denied that he was Elijah (John 1:21–23). Jesus said that John would have been the Elijah who was to come if the people of his day had accepted Jesus as their Messiah (Matt 11:14). Since they did not, John did not fulfill this prophecy about Elijah coming, though he did fulfill the prophecy about Messiah’s forerunner (Mal 3:1)."
The apostle John reveals there will be an Elijah-like prophet—as well as a Moses-like prophet—who will come in the future, during the time of the Tribulation, and he will also help prepare the way of the Lord (Rev 11:4-6). Those who hate the Lord will reject His future prophet and celebrate his death (Rev 11:7-10); however, God will resurrect him and call him to heaven (Rev 11:11-12), and render judgment upon the wicked (Rev 11:13). Malachi was the last of the OT prophets, and another prophet would not arise until John the Baptist, who would shatter the years of silence with the announcement of Jesus’ coming.
 The day of the Lord appears twice in Amos 5:18 and Zephaniah 1:14.
 Craig A. Blaising, “Malachi,” in The Bible Knowledge Commentary: An Exposition of the Scriptures, ed. J. F. Walvoord and R. B. Zuck, vol. 1 (Wheaton, IL: Victor Books, 1985), 1587.
 Tom Constable, Tom Constable’s Expository Notes on the Bible (Galaxie Software, 2003), Mal 4:5.