Again, passive aggressive behavior disguised as truth and right. Smart, these unclean spirits, and perfectly right, but totally lacking love. To address Christ they use a human being. They are really trying to get under Jesus' skin. You can feel the anxiety of the spirit, that muddy sense of self that arises in anxiety.
Anxiety is powerful.
Jesus relies on love and truth. Jesus tells them, with complete authority, to be quiet, and to leave the human they occupy alone. Again, the synagogue is amazed. Not only does he teach with authority and authenticity, but he has command over unclean spirits, over the dis-eased thought processes that assault us all. That is because Jesus IS love and truth incarnate.