You have to logically believe in the concept of God in order to serve God. If you don’t believe in God, are you going to serve God? Never!
But you know what’s really amazing? You don’t have to believe in the opponent – you don’t have to believe in Satan, our adversary, in order to serve him. Not only that; think about it, if you do believe in him 100%, you would never serve him. Never!
The finest trick of the devil is to persuade you that he does not exist.