This is a great post from fighterverses.com (and their bible memorization apps are pretty awesome, too!)
We don’t often think about our struggles or temptations as a direct assault from the enemy. In 1530, Martin Luther wrote a letter to a friend in the midst of depression and advised him in terms of spiritual warfare.
. . . Excellent Jerome, You ought to rejoice in this temptation of the devil because it is a certain sign that God is propitious and merciful to you. You say that the temptation is heavier than you can bear, and that you fear that it will so break and beat you down as to drive you to despair and blasphemy. I know this wile of the devil. If he cannot break a person with his first attack, he tries by persevering to wear him out and weaken him until the person falls and confesses himself beaten.
Whenever this temptation comes to you, avoid entering upon a disputation with the devil and do not allow yourself to dwell on those deadly thoughts, for to do so is nothing short of yielding to the devil and letting him have his way. Try as hard as you can to despise those thoughts which are induced by the devil. In this sort of temptation and struggle, contempt is the best and easiest method of winning over the devil. Laugh your adversary to scorn and ask who it is with whom you are talking. By all means flee solitude, for the devil watches and lies in wait for you most of all when you are alone. This devil is conquered by mocking and despising him, not by resisting and arguing with him. . .