Luke reports the same passage, Luke 4:33,34; he saith, There was a man which had a spirit of an unclean devil. The devil is called an unclean spirit in opposition to the Spirit of God, which is the Holy Spirit. The man that had this unclean spirit, or rather the unclean spirit in the man, cries out, Let us alone; what have we to do with thee. He doubtless feared what followed, viz. that he should be cast out. He counts himself destroyed when he cannot do mischief; like wicked men, who are the seed of this old serpent, who sleep not, except they have done mischief; and their sleep is taken away, unless they cause some to fall, Proverbs 4:16. The devil here owneth Christ to be the Holy One of God.
Related Commentaries of Mark 1:23
Mark 1:23-24
23 And there was in their synagogue a man with an unclean spirit; and he cried out,
24 Saying, Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art, the Holy One of God.