You probably know the story in Mark 5:1 – 20
Jesus is confronted by a demon possessed man of great strength. This man lived in the tombs, and had broken free of his chains and irons. Night and day he wandered among the tombs and in the hills crying out and cutting himself with stones. The demons begged Jesus to let them come out and go into the pigs and they all rushed into the lake and drowned. Those tending the pigs ran off and reported to the town’s people who went out to see what had happened. They saw the healed man sitting there, dressed and in his right mind and they were afraid. They pleaded with Jesus to leave but the man who had been demon-possessed begged to go with him. Jesus tells him “Go home to your own people and tell them how much the Lord has done for you, and how he has had mercy on you.
Jesus knows when evil is present and evil is clever enough to try to use God’s name in an effort to play on Jesus’s sympathy. Jesus is interested in more than just confronting evil – he must destroy it in order to save a man from the demons that bedevil him and give him the courage to speak of how much the Lord has done and the he has shown.