Pseudo-Chrysostom — as excerpted in the Catena Aurea on Mark 1:23-28

“(Vict. Ant. e Cat. in Marc.) Further, the Truth did not wish to have the witness of unclean spirits; wherefore there follows, And Jesus threatened him, saying, &c. Whence a healthful precept is given to us; let us not believe devils, howsoever they may proclaim the truth. It goes on, And the unclean spirit tearing him, &c. For, because the man spoke as one in his senses and uttered his words with discretion, lest it should be thought that he put together his words not from the devil but out of his own heart, He permitted the man to be torn by the devil, that He might shew that it was the devil who spoke.”