Receiving instructions from demon spirits

Why did people {smart people} German scientist's and others begin to believe Hitlers lies {He was said to have made this comment} preach it loud enough and long enough and people will believe it. And it is true faith cometh by hearing and hearing, whether it is Gods word or the devils. Why is this true? because people don't know the truth, God's word is truth, therefore lying spirits in people, news media,churches and many others deceive you why? because you did not study to show yourself approved of God. You cannot deceive someone who knows the truth,.