Rick Warren, The Purpose Driven Life, Zondervan, 2002, p. 277

"Some have raised the question of whether we can receive valid information from x themselves. Demon is portrayed in the Bible as being who have personalities and intelligence, and as beings who can and do speak. They are also portrayed as deceivers. It must therefore be concluded that they do possess some valid information. The question then becomes: Does any of this valid information get communicated to us when they speak? Obviously so, but discernment is needed to process whatever we hear from them in order to separate truth from falsehood. I once heard Ed Murphy point out this very interesting fact: Every time the words of a demon are recorded in the New Testament, they speak the truth!