There are no enemy walls that are too high or too strong for our God. This is one of the important lessons of Judges 3. If we do not continue to persevere in the faith, the Jerichos that once were conquered can again become problems. Roots of bitterness can spring up again. Secret sins can resurface.
Major doubts have a way of resurrecting themselves.
The good news is that the enemy can be driven out of Jericho again. This lesson is also found in Judges 3. No enemy forces can lay a rightful claim to this territory nor should they establish a permanent foothold in the believer's life. As Ehud removed Eglon from his illegal throne in Jericho, so believers can, by faith, see the enemy's usurping power broken in our lives. When we get to heaven we'll probably find out that there were many reasons, but two reasons emerge clearly from the text.