Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XXII

Chapter XXII.—“Rather Rejoice.”

“But still, though all demons, with all diseases, flee before you, you are not to rejoice in this only, but in that, through grace, your names, as of the ever-living, are written in heaven.  Thus also the Divine Holy Spirit rejoices because man hath overcome death; for the putting of the demons to flight makes for the safety of another.  But this we say, not as denying that we ought to help others, but that we ought not to be inflated by this and neglect ourselves.  It happens, also, that the demons flee before some wicked men by reason of the honoured name, and both he who expels the demon and he who witnesses it are deceived:  he who expels him, as if he were honoured on account of righteousness, not knowing the wickedness of the demon.  For he has at once honoured the name, and by his flight has brought the wicked man into a thought of his righteousness, and so deceived him away from repentance.  But the looker-on, associating with the expeller as a pious man, hastens to a like manner of life, and is ruined.  Sometimes also they pretend to flee before adjurations not made in the name of God, that they may deceive men, and destroy them whom they will.