These verses provide the answer to God's question in 3:1. This is the repentance that was necessary for Yahweh to return to His "wife."
4:1a The Lord clarified that for His people to return to a blessed condition they must return to Himself.
4:1b-2 If they would put away their idolatry consistently and would swear by Him, rather than by the idols, then Israel would become responsible for the nations blessing themselves (cf. Gen. 12:3; 18:18; 22:18; 26:4; Isa. 2:3; 65:16). That is, the Gentile nations would come to the Lord and so experience His blessing and would glorify Him.
". . . they will discern in the example of Israel that the source of true blessing lies in Yahweh and that he dispenses his blessings to those who are obedient to his covenant . . ."116
Swearing by the Lord means acknowledging Him as master in contrast to lord Baal (lit. master) and other lords.
4:3 This message closes with a call from the Lord to each of Jeremiah's original Jerusalemite and Judean hearers. Yahweh called on them with two agricultural metaphors. They needed to plow up the previously unplowed soil that symbolized their hearts (cf. Hos. 10:12; Mark 4:1-9). They needed to cultivate soft hearts that would welcome the Lord's words. Negatively they needed to stop investing in counterproductive ventures such as idolatry.
"Just as a farmer does not sow his seed on unplowed ground, so God does not sow His blessings in unrepentant hearts."117
4:4 Changing the figure, they should make a radical and permanent change in their commitments, a change that sprang from their innermost being (cf. 9:25-26; Deut. 10:16; 30:6; Rom. 2:28-29). Unless they did this they could count on God's judgment that would burn and consume them like unquenchable fire because their deeds were so evil. Breaking the covenant carried very serious consequences.
By repenting as the Lord and His prophet urged, Judah could have experienced a postponement of divine judgment. But Isaiah, over a century earlier, had announced that the Southern Kingdom would fall to Babylon sometime in the future.
This sermon clarifies that the essence of repentance is turning.
". . . the key to life is to be found in the direction in which one faces; if that direction is wrong, one must turn to seek the true direction and walk in that path of life."118
