New Defender's Study Bible Notes
3:1 return unto her again. The law had stipulated that a man who had divorced his wife for “uncleanness in her” (Deuteronomy 24:1,4) could not remarry her if she had then been married to another man in the meantime. Yet Jehovah was willing to take Israel and Judah back if they would repent (Jeremiah 3:14).
3:18 walk with the house of Israel. In the millennial kingdom, Judah and Israel will “come together” again, and serve the Lord together.
3:23 from the hills. It is not the hills “from whence cometh my help” (contrast Psalm 121:1, which is often incorrectly punctuated, and thus misread to imply that hills can somehow convey spiritual strength). The fact is that the hills and other such “high places” were centers of idol worship and spiritual adultery—even of physical whoredoms—leading to God’s eventual judgment on both Israel and Judah.