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 was I saw my twenty years' work beginning to totter. If I had lost my head and begun to attempt a defense by argument I should have been undone. But I was not such a fool.

"I struck instantly at the part of the man which I had best under my control and suggested that it was just about time he had some lunch. The Enemy presumably made the counter-suggestion (you know how one can never quite overhear what He says to them?) that this was more important than lunch. At least I think that must have been His line for when I said 'Quite. In fact much too important to tackle at the end of a morning,' the patient brightened up considerably; and by the time I had added 'Much better come back after lunch and go into it with a fresh mind,' he was already halfway to the door."

The devil does not plant foreign temptations in us. The devil has never tempted me to kill my enemies or to sleep with my neighbor, because those temptations would be so far removed from my own code of ethics. But the devil might plant a judgmental thought about my enemy in my mind, and then let me take it to the next step. Or the devil might whisper a thought of doubt about my husband's devotion to me, and see where that leads me. The devil can give us innocent suggestions, opening the door to further suggestions, which leads us down a path we'd never have gone on from the start.