their sons, who had remained in the land, namely, those whom the sons of Israel had not been able to destroy, Solomon made tributary, even to this day
Other versions
King James Version
Their children that were left after them in the land, whom the children of Israel also were not able utterly to destroy, upon those did Solomon levy a tribute of bondservice unto this day.English Standard Version
their descendants who were left after them in the land, whom the people of Israel were unable to devote to destruction--these Solomon drafted to be slaves, and so they are to this day.New International Version
that is, their descendants remaining in the land, whom the Israelites could not exterminate -these Solomon conscripted for his slave labor force, as it is to this day.