"The long, dull, monotonous years of middle-aged prosperity or middle-aged adversity are excellent campaigning weather for the devil"

This quote by C. S. Lewis is a reminder that life is not constantly easy which we need to be aware of the capacity for evil to creep into our lives. The "long, dull, dull years" of middle-aged life can be a time when we are most vulnerable to temptation and sin. Lewis is alerting us that throughout these years, when we might be feeling complacent or bored, we need to be extra alert and not let our guard down. We need to know the devil's tactics and not let him make the most of our complacency. We ought to strive to stay concentrated on our faith and our objectives, and not let the devil take advantage of our weak points. Lewis is reminding us that we must always be on guard and not let the devil make the most of our complacency.