What does Judges 2:20 mean?
This brings us back to a similar pronouncement, from God, made at the beginning of this chapter (Judges 2:1–5). Because of Israel's failure to purge the evil Canaanites from the land, He will stop aiding them in their conquest (Judges 2:21).There are two ways to read the beginning of this verse. It's possible to read the phrasing to mean either "in this way," or "for this reason." Either fits the meaning of the passage. The Lord's anger against Israel is expressed in allowing them to suffer oppression and violence from surrounding nations (Judges 2:16–19). At the same time, Israel's suffering is earned by their constant disloyalty to God, choosing to follow the evil sins of the Canaanites (Judges 2:11–15).
Likewise, there are two levels in which these verses are applied, in practice. Because Israel failed to follow God's directions for purging the Promised Land of evil (Deuteronomy 20:16–18), God allowed the local Canaanites to remain. This led to temptation and corruption of the people of Israel. At the same time, God chooses to no longer aid Israel in conquering territory which is part of the Promised Land. The growth of Israel, in the Old Testament, stops well short of the borders guaranteed in God's covenant with their ancestors. Israel will not control their fully allotted territory until the end times (Joshua 1:4; Revelation 20:1–6).