He cried with a loud voice; that is, the evil spirit cried out, using the organs of the man whom he possessed. What have I to do with thee, Jesus, thou Son of the Most High God? From hence it appears that, although at the great temptation of our Lord in the wilderness, Satan had but an imperfect knowledge of him: yet now, after the evidence of these great miracles, and more especially of his power over the evil spirits, there was a general belief amongst the hosts of evil that he was indeed the Son of God, the Messiah. I adjure thee by God, torment me not. The torment which he dreaded was that which tie might suffer after expulsion. So St. Luke says that they entreated him that he would not command them to depart into the abyss. Great as this mystery of evil is, we may believe that the evil spirits, although while they roam about upon this earth they are in misery, still it is some alleviation that they are not yet shut up in the prison-house of hell, but are suffered to wander about and their depraved pleasure in tempting men; so that, if possible, they may at last drag them down with them into the abyss. For they are full of hatred of God and envy of man; and they find a miserable satisfaction in endeavoring to keep men out of those heavenly mansions from which, through pride, they are themselves now for ever excluded.
For he said unto him, Come forth, thou unclean spirit, out of the man; literally, for he was saying ( ἔλεγε). The unclean spirit endeavored to arrest, before it was spoken, that word of power which he knew he must obey. So in what fellows, He was asking him ( ἐπηρώτα), What is thy name? Why does our Lord ask this question? Clearly to elicit from him an answer that would reveal the multitude of the evil spirits, and so make his own power over them to be fully known. And he saith unto him, My name is Legion; for we are many. The Roman legion consisted of six thousand soldiers. But the word is here used indefinitely for a large number. St. Luke so explains it where he says (Luke 8:30), "And he said, Legion: for many devils were entered into him." This revelation is doubtless designed to teach us how great is the number as well as the malignity of the evil spirits. If one human being can be possessed by so many, how vast must be the host of those who are permitted to have access to the souls of men, and if possible lead them to destruction! Satan here imitates him who is "The Lord of hosts." He too marshals his hosts, that he may fight against God and his people. But "for this purpose was the Son of God manifested, that he might destroy the works of the devil."