Israel was subject to forced labour in Egypt (Exodus 1:11) and had the right to subject faraway peoples who accepted an offer of peace with them to the same (Deuteronomy 20:11) as happened with the Gibeonites (Joshua 9:27). Manasseh also subjected the Canaanites, who lived in the towns they were meant to capture, to forced labour (Joshua 17:12–13). According to Deuteronomy 20:16–18, they should have instead completely annihilated these people rather than sparing them and subjecting them to forced labour—a decision which would pave the way for intermarriage and idolatry (Judges 2:1–3; Judges 3:5–6; Judges 10:6).1 Clearly the people of Ephraim were strong enough to drive out the Canaanites but they chose not to do so, maybe motived by the economic benefits that would come from having their labour. In this sense the tribes chose prosperity over obedience to God.2
10 However, they did not drive out the Canaanites who lived in Gezer, so the Canaanites have lived in the midst of Ephraim to this day but have been made to do forced labor.