So the demons begged Jesus, “If You drive us out, send us into the herd of pigs.”
Matthew 8:31. Permit us to depart into the herd of swine Some conjecture that they wished to attack the swine, because they are filled with enmity to all God’s creatures. I do admit it to be true, that they are entirely bent on confounding and overthrowing the whole order of nature which God has appointed.
Christ's power here is absolute: He commands not only disease and nature but the very demons themselves, even while in His humiliation. This victory over a legion of devils in Gentile territory is a foretaste of His conquest over Satan's whole kingdom when He enters His glory.
AI summary
Commenting on Matthew 8:28-34
And he said unto them, go, &c. He gave them leave, as God did to Satan, in the case of Job; for without divine permission, these evil spirits cannot do anything to the bodies, souls, or estates of men: they could not enter into the swine without leave, and much less do things of greater moment and consequence; and therefore are not to be feared...