God called his covenant people to conquer and occupy the land of Canaan, building there a godly civilization according to his word. He put a promise with this command. that, as they were faithful to him, he would bless their efforts with success.
In 1:18-21 Israel shows her lack of faith in God's promise in the midst of a difficult situation, which led to her failure. In 1:27-28 her unfaithfulness to God's law is seen in her attempted compromise with the enemies of God. This was a fatal mistake leading to future failures in Israel, Judges 2:2.