I think it is to show the destructive power of evil. As St John Chrysostom says:
Quote:
Now, should any one say, And wherefore did Christ fulfill the devils' request, suffering them to depart into the herd of swine? this would be our reply, that He did so, not as yielding to them, but as providing for many objects thereby. One, to teach them that are delivered from those wicked tyrants, how great the malice of their insidious enemies: another, that all might learn, how not even against swine are they bold, except He allow them; a third, that they would have treated those men more grievously than the swine, unless even in their calamity they had enjoyed much of God's providential care. For that they hate us more than the brutes is surely evident to every man. So then they that spared not the swine, but in one moment of time cast them all down the precipice, much more would they have done so to the men whom they possessed, leading them towards the desert, and carrying them away, unless even in their very tyranny the guardian care of God had abounded, to curb and check the excess of their violence. Whence it is manifest that there is no one, who does not enjoy the benefit of God's providence. And if not all alike, nor after one manner, this is itself a very great instance of providence; in that according to each man's profit, the work also of providence is displayed.
And besides what has been mentioned, there is another thing also, which we learn from this; that His providence is not only over all in common, but also over each in particular; which He also declared with respect to His disciples, saying, "But the very hairs of your head are numbered." (Matthew 10:30) And from these demoniacs too, one may clearly perceive this; who would have been choked long before, if they had not enjoyed the benefit of much tender care from above.
For these reasons then He suffered them to depart into the herd of swine, and that they also who dwelt in those places should learn His power. For where His name was great, He did not greatly display Himself: but where no one knew Him, but they were still in an insensible condition, He made His miracles to shine out, so as to bring them over to the knowledge of His Godhead. For it is evident from the event that the inhabitants of that city were a sort of senseless people; for when they ought to have adored and marvelled at His power, they sent Him away, and besought Him that He would depart out of their coasts.
But for what intent did the devils destroy the swine? Everywhere they have labored to drive men to dismay, and everywhere they rejoice in destruction. This, for instance, the devil did with respect to Job, although in that case too God suffered it, but neither in that case as complying with the devil, but willing to show His own servant the more glorious, cutting off from the evil spirit all pretext for his shamelessness, and turning on his own head what was done against the righteous man. Because now also the contrary of what they wished came to pass. For the power of Christ was gloriously proclaimed, and the wickedness of the demons, from which He delivered those possessed by them, was more plainly indicated; and how they want power to touch even swine, without permission from the God of all.
And if any would take these things in a hidden sense, there is nothing to hinder. For the history indeed is this, but we are to know assuredly, that the swinish sort of men are especially liable to the operations of the demons. And as long as they are men that suffer such things, they are often able yet to prevail; but if they have become altogether swine, they are not only possessed, but are also cast down the precipice. And besides, lest any should suppose what was done to be mere acting, instead of distinctly believing that the devils had gone out; by the death of the swine this is rendered manifest.
Also, the swine are a teaching moment. The fathers write that there's a kind of worse insanity than what the possessed man had - that is to tell Jesus Christ to go away. To prefer having a crazy, naked, scary person running around terrorizing people and our pigs to no pigs and people being saved. They were afraid, so they asked him to leave.
I think that's the real takeaway here, a comparison of the demoniac and the people of the town. Jesus tells the man "Go and tell what the Lord/God (Mark/Luke) has done for you" and he goes telling what
Jesus has done for him - remember that next time someone tries to tell you, the bible never says Jesus is God.
Anyway you have the crazy person who was terrorizing people, and then you have these normal "sane" people. The crazy person is saved, and the normal, sane people tell the Savior to leave, gripped with fear. They were told
how the demoniac was cured by the herdsmen, so the swine are the story as it were. So there's a cautionary tale here, not to judge, not to confuse the measure of men in this world - normal, upright citizens who appear sane - with the way God judges.
