Mark 5:13

And he gave them leave. And the unclean spirits came out, and entered into the swine: and the herd rushed down the steep into the sea, in number about two thousand; and they were drowned in the sea.

We reject views like that of Barclay who thought that the cries of the man frightened the swine into their destruction, and that the Lord used this to "convince" the man the demons had left him; and also the view that the hogs committed suicide rather than allow the demons to possess them! Mark here stated that the demons entered the swine, and there is no reason for dissociating their immediate destruction from that evident cause of it.

Here is a great difficulty in the eyes of some; but it is a difficulty founded on prior disbelief of demon-possession and the power of the incarnate God in Christ. The destruction of the swine was necessary in order that Christ might thereby show what is the true intent and purpose of Satan. If people desire to know what Satan is and what he will do to them who permit his evil domination, let them behold the example of these swine. Look what Satan did to the family of Job in a single day; solely because he had God's permission to do it. From the gates of Paradise to the present hour, Satan has had one invariable purpose, that of the total destruction of man. The example of the swine is an instructive example of Satan's perpetual intent. But what about the property issue? Christ did not destroy the swine; the demons did. Christ's permission of such a thing is no more than God's permission of all natural disorders like earthquakes, volcanoes, floods, droughts, and tornadoes, etc., which kill millions of people (not swine alone); and yet all thoughtful persons find no difficulty reconciling this with God's love and justice.