I am wondering how far we can ascribe to the work of the Devil those very legitimate desires that we indulge in. Some people have a very sensitive conception of the presence of the Devil. Others haven’t. Is the Devil as real as we think he is? That doesn’t trouble some people, since they have no desire to be good, but others are continually harassed by the Old Man himself.
No reference to the Devil or devils is included in any Christian Creeds, and it is quite possible to be a Christian without believing in them. I do believe such beings exist, but that is my own affair. Supposing there to be such beings, the degree to which humans were conscious of their presence would presumably vary very much. I mean, the more a man was in the Devil’s power, the less he would be aware of it, on the principle that a man is still fairly sober as long as he knows lie’s drunk. It is the people who are fully awake and trying hard to be good who would be most aware of the Devil. It is when you start arming against Hitler that you first realize your country is full of Nazi agents. Of course, they don’t want you to believe in the Devil. If devils exist, their first aim is to give you an anaesthetic — to put you off your guard. Only if that fails, do you become aware of them.
"Answers to Questions on Christianity," God in the Dock (Eerdmans: 1970) 56-57.