Albert Barnes Commentary Joel 3:7

"behold, I will stir them up out of the place whither ye have sold them, and will return your recompense upon your own head;" — Joel 3:7 (ASV)

Behold, I will raise them — If this promise relates to the same individuals who had been sold, it must have been fulfilled silently, as indeed the return of captives to their own land, unless brought about by some historical event, does not belong to history but to private life. The prophet, however, is probably predicting God’s dealings with the nations, not with those individuals.

The enslaving of these Hebrews in the time of Joram was only one instance out of a whole system of covetous misdeeds. The Philistines carried away captives from them again in the time of Ahaz (2 Chronicles 28:18), and yet again subsequently (Ezekiel 16:27; Ezekiel 16:57); and still more at the capture of Jerusalem (Ezekiel 25:15).