The strangers are the non-Israelite population of the holy land, the descendants (chiefly) of those Canaanites whom the children of Israel did not drive out. The reimposition of the bond-service imposed on the Canaanites at the time of the conquest Judges 1:28, Judges 1:30, Judges 1:33, Judges 1:35, but discontinued in the period of depression between Joshua and Saul, was (it is clear) due to David, whom Solomon merely imitated in the arrangements described in these verses.