Commentaries:
Jamieson, Fausset, and Brown
And thou—rather, "And if (carried on from Jeremiah 4:1) thou shalt swear, 'Jehovah liveth,' in truth, etc.", that is, if thou shalt worship Him (for we swear by the God whom we worship; compare Deuteronomy 6:13; Deuteronomy 10:20; Isaiah 19:18; Amos 8:14) in sincerity, etc.
and the nations—Rather, this is apodosis to the "if"; then shall the nations bless themselves in (by) Him" (Isaiah 65:16). The conversion of the nations will be the consequence of Israel's conversion (Psalms 102:13, Psalms 102:15; Romans 11:12, Romans 11:15).
Other Jamieson, Fausset, and Brown entries containing Jeremiah 4:2:
Isaiah 65:16
Jeremiah 4:1
Jeremiah 5:2
Jeremiah 5:7
Jeremiah 12:16
Jeremiah 22:24
Hosea 4:15
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.