Mal 4:1 MKJV  For behold, the day is coming, burning like a fire pot; and all the proud, and every doer of wickedness, shall be chaff. And the coming day will set them ablaze, says Jehovah of Hosts, which will not leave root or branches to them.

Barnes: For, behold, the day cometh, which shall burn as an oven – He had declared the great severance of the God-fearing and the God-blaspheming, those who served and those who did not serve God; the righteous and the wicked; now he declares the way and time of the severance, the Day of Judgment. Daniel had described the fire of that day, Dan_7:9-10, “The throne (of the Ancient of days) was a fiery flame; his wheels a burning fire: a fiery stream issued and came forth from Him: the judgment was set and the books were opened.” Fire is ever spoken of, as accompanying the judgment Psa_50:3. “Our God shall come, and shall not keep silence, a fire shall devour before Him Isa_66:15-16. Behold the Lord will come with fire: for by fire and by the sword will the Lord plead with all flesh: 1Co_3:13 every man’s work shall be made manifest, for the day shall declare it, because it shall be revealed by fire: and the fire shall try every man’s work, of what sort it is.” Peter tells us that fire will be of this burning world; 2Pe_3:7-10. “the heavens and the earth which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of’ ungodly men; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.”

Russell: The day cometh — Typically in 70 AD when Israel’s national existence was destroyed.

Particularly referring to the special trials which the day of the Lord’s presence would bring with it. The Day of Vengeance.

Burn as an oven — The fire of God’s indignation against unrighteousness during the day of Christ. Melting and dissolving the present earth–human society as now organized under Satan’s control.

With the fire of God’s jealousy. (Zep_3:8)

“Seek meekness, seek righteousness, it may be that ye shall be hid in the day of the Lord’s anger.” (Zep_2:3)

Shall burn them up — All evil systems, errors and willful sinners. Burn up evil throughout the entire Millennial age. At the end of the Millennium there will be no proud people on the earth.

Not consuming the individuals. They will cease to be “tares,” but not cease to be human beings.

Root nor branch — Completely consuming their hypocrisies and pretended devotions to the Lord.
Until every root and branch of sin is thoroughly consumed. Those refusing to come into harmony with righteousness will be destroyed in the Second Death.

Guzik:. Leave them neither root nor branch: In that coming day the wicked will have no hope of shooting up again to life. As long as a root remains there is hope, but hope is gone for these because the judgment of eternity is final.

Mal 4:2 MKJV  But to you who fear My name, the Sun of Righteousness shall arise, and healing will be on His wings. And you shall go out and frisk like calves of the stall.

Adam Clarke : You that fear my name – The persons mentioned in the sixteenth verse of the preceding chapter, ye that look for redemption through the Messiah.

The Sun of righteousness – The Lord Jesus, the promised Messiah; the Hope of Israel.
With healing in his wings – As the sun, by the rays of light and heat, revives, cheers, and fructifies the whole creation, giving, through God, light and life everywhere; so Jesus Christ, by the influences of his grace and Spirit, shall quicken, awaken, enlighten, warm, invigorate heal, purify, and refine every soul that believes in him, and, by his wings or rays, diffuse these blessings from one end of heaven to another; everywhere invigorating the seeds of righteousness, and withering and drying up the seeds of sin. The rays of this Sun are the truths of his Gospel, and the influences of his Spirit. And at present these are universally diffused.

Russell: But unto you — A remnant of nominal spiritual Israel who heed the Word of the Lord. To them belong the blessings of his special favor. It is the Jews who see the Sun of Righteousness arise.

Sun of righteousness — The Redeemer and his elect Church. A synonym for the spiritual seed of Abraham.

“Then shall the righteous shine forth as the sun.” (Mat_13:43)

We have not yet experienced the rising of the Sun of Righteousness, but we have with us the early gray dawn. We will not be here when the Sun “rises.” We are now in the dawn, but there is quite a while between the first dawn of day and the sunrise.

With healing — For the cure of all the masses of the earth With restitution, blessing all the families of the earth.

The final result will be that there shall be no more sighing, no more crying, no more dying. Refreshment and life–mental, moral and physical–upon the world of mankind. Illuminating the whole earth with the knowledge of the glory of the Father, which will result in the healing and blessing of all the families of the earth.

Mal 4:3 MKJV  And you shall trample the wicked, for they shall be ashes under the soles of your feet in the day which I am preparing, says Jehovah of Hosts.

Adam ClarkeYe shall tread down – This may be the commission given to the Romans: Tread down the wicked people, tread down the wicked place; set it on fire, and let the ashes be trodden down under your feet.

Russell: Tread down — As ashes. Indicating the completeness of the victory of righteousness over sin.

The wicked — Sin and the workers of iniquity–a strong figure of sin’s complete defeat.

Guzik: You shall trample the wicked: When God’s people see the final resolution of all things they will be so happy they will jump about like stall-fed calves set free from the pen. As they jump about with joy, the wicked are trampled beneath their feet.

Mal 4:4 MKJV  Remember the Law of Moses My servant, which I commanded to him in Horeb for all Israel, the statutes and judgments.

Adam ClarkeRemember ye the law of Moses – Where all these things are predicted. The Septuagint, Arabic, and Coptic, place this verse the last.

Russell:The law of Moses — Typifying the law of love. The man Christ Jesus, by full obedience to the Law covenant, superseded Moses as the Lawgiver, of whom Moses said: “A prophet shall the Lord your God raise up unto you like unto me. Him shall ye hear in all things.” (Act_3:22) “The Law was given by Moses, but grace and truth came by Jesus Christ.” (Joh_1:17)

Mal 4:5 MKJV  Behold, I am sending you Elijah the prophet before the coming of the great and dreadful day of Jehovah.

Adam Clarke  –Behold, I will send you Elijah the prophet – This is meant alone of John the Baptist, as we learn from Luk_1:17 (note), in whose spirit and power he came.

Russell: Send you Elijah — The Christ in the flesh, Head and Body. The name signifying “God (mighty one) of Jehovah” or “My God is Jehovah,” a fit name for the Lord’s Anointed, whose work will be to restore all things.

John the Baptist fulfilled this prediction so far as fleshly Israel was concerned. John the Baptist stood for a multitudinous Elijah as Jesus stood for a multitudinous Christ.

Though John came in the spirit and power of Elias (Luk_1:17) and would have fully answered as his antitype if he had been received, yet he was not the Elias, the Great Prophet, referred to by  Malachi.

Before the coming — The coming of Elijah must precede the Day of the Lord; but his work belongs to that day. It is important to show that Elijah has come before the return of the Lord.

Day of the LORD — will end with the complete overthrow of worldly and Satanic dominion in the earth and the full investiture of Christ Jesus and his saints with power and dominion.

Guzik: — Elijah the prophet: Why Elijah? Because he ministered in a time of crisis in Israel, when the nation was far from God, and a time that immediately preceded a terrible judgment.
It is significant that in these closing words of the Old Testament, God makes reference to both Moses and Elijah. They both met God at Mount Sinai (Exo_3:1; 1Ki_19:8-18). They also both met Jesus at the Mount of Transfiguration (Mat_17:1-5).

Mal 4:6 MKJV  And he shall turn the heart of the fathers to the sons, and the heart of the sons to their fathers, that I not come and strike the earth with utter destruction.

Russell: He shall turn — Endeavor to bring about harmony, reconciliation and fellowship between God and his people. In its kingly office, the Church shall effect for the world what it fails to do as the Elijah teacher.

The heart — Sentiment.

To the children — To childlikeness.

And the heart — Would seem to mean the establishment in the earth of a spirit of reciprocal love.

To their fathers — To harmony with the faithful patriarchs and prophets.

Lest – A conditional statement–if he succeeds, the earth will not be smitten; but if he succeeds not, the curse will come.

It was not prophesied that Elijah would have success. Other scriptures clearly indicate that no such reform will occur, and that the “curse” or trouble will surely come. The antitypical Elijah, the Church in the flesh, will fail to establish righteousness and love on the earth, fail to bring about reconciliation.

With a curse — The great time of trouble.

When John the Baptist failed to turn Israel to repentance and they crucified the Lord. Hence the curse, or time of trouble, came upon that nation, destroying it in AD 69-70,

But it shall not be utterly cursed and forever destroyed because the exalted Elijah–Christ shall put down all opposition and then restore and bless.  

That the curse, the trouble, will be effective and yield blessed results is distinctly shown in Zep_3:8-9.