Behold, I will raise them, &c. I will restore them, or their posterity, out of their several captivities whither their enemies have dispersed them. Grotius on this place mentions, that Alexander and his successors set at liberty many Jews, who were slaves in Greece. Many also, on occasion of Cyrus's decree, might return to their country, from such parts of Asia Minor and the Ionian islands as were subject to that monarch. And will return your recompense upon your own head Will inflict upon you the punishments mentioned in the following verse. I will sell your sons, &c. This was fulfilled when Alexander took Gaza, Zidon, and Tyre, and made a great multitude of captives, of whom he is said to have sold thirty thousand for slaves. These captives the Jews, who were in favour with him, had the liberty of buying, and probably afterward sold many of them, by way of traffic, to the Arabians, here meant by the Sabeans.
Related Commentaries of Joel 3:7
Joel 3:7-8
7 Behold, I will raise them out of the place whither ye have sold them, and will return your recompence upon your own head:
8 And I will sell your sons and your daughters into the hand of the children of Judah, and they shall sell them to the Sabeans, to a people far off: for the LORD hath spoken it.