What does Mark 5:13 mean?

In order to save a man tormented by demons, Jesus allows the demons to enter a herd of pigs. Note that He neither suggests, orders, nor even indicates that He anticipates the imminent destruction of the pigs. Despite being a Jew under the Mosaic Law, He is not on a personal crusade to save foreign Gentiles from pigs. Jesus' entire purpose here is to save a man. While He undoubtedly knows the demons will kill the pigs, He is not responsible for those actions. He is aware that homeless demons feel unsettled (Matthew 12:43–44) and that people are far more important than animals (Matthew 6:26; 12:12). He would also know that under normal circumstances, pigs don't have a herd instinct that would lend them to stampeding down a hill to their doom. When frightened, a group of pigs scatter. And pigs can swim.

So this verse says very little about Jesus' character—or that of the pigs—and much about the nature of demons. Throughout history, demons have been worshiped by dark occultists who wish to tap into their ungodly spiritual power. Lately, however, demons have increasingly been portrayed in popular fiction as sympathetic characters wronged by their Creator-tyrant and denied the opportunity for forgiveness. Alternatively, they are used as monsters that a human foe, with or without the use of magic, can defeat.

These portrayals are wrong and dangerous. Demons live in a state of total rebellion against God. They are compelled to subjugate themselves to Him (Mark 5:6), but they do not worship Him as their Lord. Although they pretend to be our allies, they wish nothing more than our destruction. And we do not have the spiritual power to defeat them; even Michael the archangel would not rebuke Satan in his own authority (Jude 1:9). The pigs, stampeding against their instincts and drowning despite their abilities, serve as a vivid illustration for us of the treacherous and destructive force of demons.