What does Judges 3:3 mean?
The Lord has said that He has left the nations that remained in existence at the time Joshua died. God has not brought these nations to an end or driven them out of the region of Canaan. That was God's command to Israel (Deuteronomy 20:16–17), so the people would not follow the horrific evil of those cultures (Deuteronomy 20:18). But Israel disobeyed the Lord and stopped well short of their goal (Judges 2:20). And so, God intends to use these nations against His rebellious people. He will demonstrate by example; God will "test" Israel for their response to the hardships of war (Judges 2:21–22).Reading the book of Judges, it seems the Canaanites plagued Israel in two primary ways. One was through temptation to idolatry (Judges 2:11–13), coming from those the people of Israel allowed to remain in the land (Judges 3:5). The others, listed here, are the nations living in areas not fully conquered by Israel.
The Philistines, known for their five lords, were sometimes called the Sea Peoples. Said to have originated on the island of Crete, they had migrated to the shores of the Mediterranean in Palestine at some point. They eventually came to hold five city-states in Canaan, including Ashdod, Ashkelon, Ekron, Gath, and Gaza. Together, these were called the Pentapolis and were ruled by the five chieftains mentioned in this verse. The Philistines became longtime enemies of Israel in the region.
"All the Canaanites" seems to be a general term for all the non-specific people groups in Canaan that would war against Israel in the coming generations. The Sidonians may have eventually been better known as the Phoenicians. The Hivites are identified as occupying a mountainous region north of the Sea of Galilee. While they live in their own territories, the reach of these nations covered the entire Promised Land. All of Israel would be impacted by the wars they would bring against God's people.