I recently came across an excellent illustration that manifests the difference between intellectual faith and genuine faith. In the late 1890's, a famous tightrope walker strung a wire across Niagara Falls. As 10,000 people watched, he inched his way along the wire from one side of the falls to the other.
When he got to the other side, the crowd cheered wildly. Finally, the tightrope walker was able to quiet the crowd and shouted to them, 'Do you believe in me?'. The crowd shouted back, 'We believe! We believe!'.
Again, he quieted the crowd and shouted to them, 'I'm going back across the tightrope but this time I'm going to carry someone on my back. Do you believe I can do that?'. The crowd yelled back, 'We believe! We believe!'. He quieted the crowd one more time and then asked them, 'Who will be that person?'.
The crowd suddenly became silent. Not a single person was willing to apply the very truth that they professed to believe in--that the tightrope walker could cross the falls with a person on his back.
We may believe that Jesus is the Son of God, but does our faith surpass the faith of demons? Are we willing trust our lives with Jesus? Are we willing to follow Him regardless of the cost?
In the English language, it's curious that the word evil is "live" spelled backwards. And indeed, evil always destroys. Life is diminished if not wiped out where the demons’ rule. The death of the pigs reflects that. What's more, in the Ancient Near East, the sea represented one of the forces of chaos that people feared. So, it's a double-whammy: first there is death but second there is death by drowning in the sea, thus piling up and compounding the sense of chaos and evil in this story.
But the sad spectacle of those hapless pigs rushing headlong into the sea also reminds us that the expelling of evil from our world always involves sacrifice. For whatever the reason, God does not simply wave a magic wand to eliminate evil. Rooting out evil takes time, takes effort, and takes above all sacrifice. This should hardly come as any surprise, however, to people who live their lives in the shadow of a cross.
One final point, however: Jesus was chased away by the townsfolk, but the healed man remained and according to verse 39, he kept on talking about what Jesus had done. Something about his ongoing witness reminds us that this is also our role: lots of people in this world try to chase Jesus away. Our task is to hang around anyway and to just keep talking, just keep witnessing to Jesus' work, and just keep hoping that at the end of the day, that witness will bring people back to the very Jesus they once chased away. "Return home and tell how much God has done for you," Jesus told this man. He tells the rest of us the exact same thing.