And there was there a herd of many swine feeding on the mountain: and they besought him that he would allow them to enter into them. And he allowed them.
Read Chapter 8
Ambrose of Milan
AD 397
People are the authors of their own tribulation. If someone did not live like a swine, the devil would never have received power over him. If he did receive power, it would be power not to destroy but to test him. After the Lord’s coming, the devil could already not corrupt the good, so perhaps he now does not seek the destruction of all people but only of the fickle. A mugger does not lie in wait for armed men but for the defenseless. He who understands that the strong will despise him or the powerful destroy him troubles only the weak with wrongs. Someone says, “Why does God permit this to the devil?” I say, “So that good people may be tested and the wicked punished, for this is the punishment of sin.” This is also according to the law, because the Lord sends fever, trembling, evil spirits, blindness, and all scourges according to the punishment of sinners. –.
And there was there an herd of many swine (about two thousand, S. Mark 5:2) feeding on the mountain (nigh unto the mountain, S. Mark , ibid.). But for what purpose were these swine, inasmuch as they were forbidden to the Jews by the law of Moses? Gadara, although a city of Judæa or rather of Galilee, had, according to Josephus, been assigned by Cæsar for a dwelling-place to the Syrians and Gentiles; who were not prohibited from keeping swine. And again, the Jews might have been feeding the swine, not for their own eating, but for other purposes: to sell them to the Gentiles for the use of the Roman soldiery, or in order to provide lard for the greasing of their chariot wheels.
And they besought Him that He would suffer them to enter into them. The devils made this request:
1. In order that, inasmuch as they were unable to injure men directly, they might injure them indirectly through their property or possessions.
2. That, as actually came to pass, they might stir up the ill-will o...
The Gadarenes established a ruling for themselves that they would not come out or view the signs of our Lord. Consequently he drowned their swine so that they would have to come out against their will. “Legion,” which had been chastened, is a symbol of the world. He commanded the demons to enter the swine and not the man. He, concerning whom they had said, “It is by Beelzebub that he casts out,” engaged in battle against Satan on the mountain and against Legion, the chief of his force. When they entered the swine, he drowned them at that very moment. The force of the merciful One who was keeping watch over this man was known by this. They were begging him not to send them out of that region and not to send them to Gehenna. Commentary on Tatian’s Diatessaron
If, says St. Athanasius, the infernal spirits have no power over such impure beasts as swine, with much greater reason then are they deprived of power over man, who is made after God's own image, and redeemed by the blood of his son, Christ Jesus. We should therefore fear only God, and despise the devil. (Life of St. Anthony)