God left some people behind who will challenge the others militarily and spiritually. Today we see some examples of how they responded. The pattern is the same throughout the book of Judges. The people sin, they are oppressed and they are delivered. The story of Ehud gets a bit graphic and we are probably told that he is left-handed because it allowed him to conceal a weapon on his right side where the guards would not have looked for one.
James 1:2-16 gives us a similar view of the difficulties we face in life. Without them, we would become weak. For us and for Israel, the challenges should make us stronger, but they can also cause us to fail. Unfortunately for Israel, failure was the common response.