Theophylact of Ohrid
Catena Aurea · Markusevangelium 1
And at even, when the sun did set, they brought unto him all that were diseased, and them that were possessed with devils. And all the city was gathered together at the door. And he healed many that were sick of divers diseases, and cast out many devils; and suffered not the devils to speak, because they knew him.
Furthermore, the reason that He forbade the devils to speak, was to teach us not to believe them, even if they say true. For if once they find persons to believe them, they mingle truth with falsehood.