In the Evangelical world many think that the job of Satan is to make you believe that he does not exist. This mythical character who evolved from the light bearer is said to be doing his job so very well, and preachers want to enforce again that he is real. They scare you with the Devil.
In yet another part of the Buybull he is said to be going around like a roaring lion seeking those whom he can devour. Sorry folks. You can't have it both ways. I suppose this is what happens when 66 books about mythical beings are all put together. Stop worrying and enjoy your life.