Albert Barnes Commentary Jeremiah 3:1

"They say, If a man put away his wife, and she go from him, and become another man`s, will he return unto her again? will not that land be greatly polluted? But thou hast played the harlot with many lovers; yet return again to me, saith Jehovah." — Jeremiah 3:1 (ASV)

They say - Or, That is to say. The prophet has completed his survey of Israel’s conduct, and draws the conclusion that as an adulterous wife could not be taken back by her husband, so Israel has forfeited her part in the covenant with God. Apparently the opening word, which literally means “to say,” only introduces the quotation in the margin.

Yet return again to me - Or, “and do you think to return to me!” The whole argument is not of mercy, but is the proof that after her repeated adulteries, Israel could not again take her place as wife. To think of returning to God, with the marriage-law unrepealed, was folly.