Temptations are almost always based on our own legitimate wants and needs. Desire for food, desire for human intimacy, or desire for approval from others is not from the devil. These are normal, perhaps even innocent, desires, but they do at times make us more vulnerable to temptation. C. S. Lewis's The Screwtape Letters (1943) are fictional letters written from one devil to another. In one letter Screwtape writes to Wormwood:

"I once had a patient, a sound atheist, who used to read in the British Museum. One day, as he sat reading, I saw a train of thought in his mind beginning to go the wrong way. The Enemy, of course, was at his elbow in a moment. Before I knew where I…