How will Hashem sell their children "b'Yad Bnei Yehudah"?
Radak: He will hand them over into the hands of Bnei Yehudah, and they will sell them to Sheva'im.
Malbim (7): When the Yevanim came and destroyed Tzor and Tzidon, they brought their sons and daughters to Yavan. There, the Yehudim exiled there (via Bnei Yavan) bought them and sold them to Bnei Sheva, a distant nation, to distance them from their border. It turns out that they were punished via the same Yehudim that they sold, and in the same Midah that they did evil to them!
Who are "Sheva'im"?
Rashi: They are the people of Shva 1 .
We find that Malkas Shva came to see Shlomo ha'Melech (Melachim I, Perek 10). (PF)
Where did Hashem say so?
Rashi: "[Arur Kena'an] Eved Avadim Yihyeh l'Echav" (Bereishis 9:25).
