After the storm, Jesus and the disciples arrive safely in the country of the Gerasenes (or Gadarenes; different texts say different towns, and they’re both near enough to be plausible). They are met by a demon-possessed man who has been greatly tormented. The demons know who Jesus is and are afraid of Him and ask Him not to torment them. As an alternative, they offer to go into a nearby herd of pigs. Jesus agrees, and the legion of demons drive the pigs mad so that they rush into the lake and drown. This understandably freaks the pigherds out, and they go tell everyone around what happened. The people come to see what has happened and seeing the ex-demoniac acting like a normal, healthy person frightens them too. They ask Jesus to leave the area, so He does. But before He can leave, the man asks to go with Him, but Jesus sends him back to his home, this time telling him to share freely what God has done for him.
We learn from this story that demons know who Jesus is, and that He has power and authority over them. They call Him “Son of the Most High God” (v. 28) and beg Him not to send them to the abyss (v. 31). We also learn that mental illness can be caused or exacerbated by demons, which is not to say all mental illness necessarily is.
Jesus’s ministry was focused on teaching His own countrymen, the Jews, so it is a little strange that He went to this Gentile area in the first place. (Jews wouldn’t keep pigs, after all.) But He doesn’t ignore Gentiles completely when He encounters them, maintaining the idea that God’s plan of salvation includes all people. (See God’s covenant with Abraham, Peter’s dream, and all of Paul’s letter to the Romans.)
Give us compassion for those in hard circumstances, and help us care for them as You would.