And he healed many that were sick of various diseases, and cast out many demons; and allowed not the demons to speak, because they knew him.
All Commentaries on Mark 1:34 Go To Mark 1
George Leo Haydock
AD 1849
The devils knew that it was Christ, who had been promised for so many ages before; for they saw him perform the wonders which the prophets had foretold of him; yet they were not perfectly acquainted with his divine nature, or otherwise they never would have persecuted to death and crucified the Lord of glory. (St. Augustine)
But Christ would not permit them to declare that they knew him. (Bible de Vence)
See Luke iv. 41.