From The Explanation of the Gospel of St. Luke
by Blessed Theophylact, Archbishop of Ochrid and Bulgaria
26-33. And they arrived at the country of the Gadarenes, which is across from Galilee. And when He went forth to land, there met Him out of the city a certain man, possessed by demons for a long time, who wore no clothes, neither abode in any house, but in the tombs. When he saw Jesus, he cried out, and fell down before Him, and with a loud voice said, What have I to do with Thee, Jesus, Son of God most high? I beseech Thee, torment me not. (For He had commanded the unclean spirit to come out of the man. For oftentimes it had caught him: and he was kept bound with chains and in fetters; and he broke the bands, and was driven by the demon into the wilderness.) And Jesus asked him, saying, What is thy name? And he said, Legion: because many demons were entered into him. And he besought Him that He would not command them to go out into the abyss. And there was there an herd of many swine feeding on the mountain: and they besought Him that He would suffer them to enter into them. And He suffered them. Then went the demons out of the man, and entered into the swine: and the herd ran violently down a steep place into the lake, and were drowned. See how the demon is torn between two wicked passions: impudence and fear. When he says, What have I to do with Thee? he shows the impudence of a shameless slave; when he says, I beseech Thee, he shows his fear. He was dwelling among the tombs because he wanted to instill in men the false suspicion that the souls of those who have died become demons. The demons ask not to be cast into the abyss, but that they be permitted to remain a while longer upon the earth. The Lord permits them to remain upon the earth so that they might fight and contend with men, and thus render men tested veterans. If man had no adversaries, there would be no struggles and contests; and if there were no contests, there would be no crowns of victory. There is a more spiritual sense which you should learn as well: the man who has demons within him and wears no garment and makes his home outside the house, is anyone who does evil and demonic deeds, who has stripped himself of his baptismal robe, and dwells outside the Church. Such a man is not worthy to enter into the Church, but instead he lives in the tombs of dead and rotting deeds, for example, in brothels and in the chambers of publicans and graft. These are indeed tombs of iniquity.
34-39. When they that fed them saw what was done, they fled, and went and told it in the city and in the country. Then they went out to see what was done; and came to Jesus, and found the man, out of whom the demons were departed, sitting at the feet of Jesus, clothed, and in his right mind: and they were afraid. They also which saw it told them by what means he that was possessed of the demons was healed. Then the whole multitude of the country of the Gadarenes round about besought Him to depart from them; for they were taken with great fear: and He went up into the boat, and returned back again. Now the man out of whom the demons were departed besought Him that he might be with Him: but Jesus sent him away, saying, Return to thine own house, and tell what great things God hath done unto thee. And he went his way, and proclaimed throughout the whole city what great things Jesus had done unto him. When those who had been feeding the swine fled into the city, it became an opportunity for salvation for the Gadarenes, but they did not understand. They ought to have marvelled at the Saviour's power and believed in Him. The Evangelist says that they besought Him to depart from them, instead of calling upon Him in supplication. They did this out of fear of suffering another loss like that of the swine. But the man who had been healed shows indisputable proof of his healing. That he had been healed in his mind is shown by the fact that he now both recognizes Jesus and begs His permission to be with Him. For he was afraid, it would seem, that the demons would again easily assault him when he was separated from Jesus. But the Lord shows him that even if he is not with Jesus, the Lord's grace can shelter him from demonic attack. The Lord says to him, Return to thine own house, and tell what great things God hath done unto thee. By not saying, "what great things I have done unto thee," the Lord gives us an example of humility and teaches us that we should attribute all our accomplishments to God. But though the Lord had commanded him to tell what things God had done for him, he told instead what things Jesus had done for him, so great was his gratitude. Therefore when you do something good for someone, do not desire it to become public knowledge; but he who is the beneficiary of that good deed ought to be moved by gratitude to tell it to others, even though you do not want him to do so.