Malachi’s final message contains two distinct but related speeches. The first emphasizes serving the Lord (Malachi 3:13–18). The second compares the fate of the wicked and the righteous (Malachi 4:1–3)
Each speech ends with the messenger formula (see study note on Malachi 1:8). The prophet revisits themes from the fourth message (Malachi 3:1–5), emphasizing God's desire for honesty and faithfulness in worship, especially with the coming judgment on the day of the Lord.
If Malachi is like a courtroom scene, this last argument is the sentencing. Although wickedness seems to win over righteousness and God seems slow to judge sin in the community, the coming day of the Lord will prove God's justice. The wicked will be separated from the righteous by the fire of God's judgment.