"The demons have also the following trick. They cry out the names of those whom they know to have none of the merits of holiness and to possess none of the fruits of the Spirit. They pretend to be burnt up by the merits of such people and to take flight from the bodies of the possessed.
Deuteronomy has this to say about such persons: 'If a prophet should arise among you or a man claiming visionary dreams, and if he foretells a sign and a portent, and if what he says should actually happen, and if he should say to you, "Let us go and follow strange gods who are unknown to you and let us serve them," do not listen to the words of that prophet or dreamer. For the Lord your God is putting you to the test, bringing out into the open whether or not you love Him with all your heart and with all your should (Deuteronomy 13: 1 - 3).
And in the gospel he says this: 'Fake Christs and fake prophets will rise up and they will perform great signs and wonders so that if possible even the chosen will be led into error' (Matthew 24:24)." ~REF:St. John Cassian, "Conferences," - (Trans Colm Luibheid, New York: Paulist Press, 1985), pp. 174 - 176