Why Do Some Battles Never Go Away?

For what reason would God allow a battle to remain in my life over which He could give me the victory in a moment of time? The devil will try to captivate us and attempt to convince us that the battles we face are bigger than the Christ in us. God will leave these trials in our life to train our hands for war and to cause us to depend on the power of the Holy Spirit. We need to understand our enemies are already defeated but we still need to go to Jesus to get the resources and to stand in faith. If we lose sight of God in these trials we will turn to human reasoning and begin to follow our own sensual nature and desires.