In the old dispensation, God promised that the faithful nation of Israel would experience economic and political prosperity, rising far above all other nations. Israel would be the head of nations, and not the tail (Deuteronomy 26:19; Deuteronomy 28:1, Deuteronomy 28:13), so that God’s favour was clearly visible to all. Conversely, God warned that unfaithful Israel would experience God’s disfavour, which would be clearly displayed by other nations gaining economic and political ascendency over Israel. Israel would be the tail of the nations, not the head (Deuteronomy 28:44).
But what applied to the nation as a whole could not be applied to every individual Israelite, as though every righteous Israelite who served God faithfully would always experience health and prosperity, and that every wicked Israelite who did not serve God faithfully would always experience sickness and adversity.
At the time when this verse was written, God’s people were, generally speaking, guilty of numerous transgressions and shortcomings, as the prophecy of Malachi shows. Accordingly, the Israelites as a whole experienced economic and political hardships. There was no discernible difference in the life conditions of those in Israel who feared the Lord (Malachi 3:16) and those who did not. But in Malachi 3:17–18, the Lord assures the righteous who feared him and served him faithfully that the day was coming when the righteous would be rewarded, and the wicked would be punished.
18 Then once more you shall see the distinction between the righteous and the wicked, between one who serves God and one who does not serve him.