And when He came out onto the land, He was met by a man from the city who was possessed with demons; and who had not put on any clothing for a long time, and was not living in a house, but in the tombs. Seeing Jesus, he cried out and fell before Him, and said in a loud voice, “What business do we have with each other, Jesus, Son of the Most High God? I beg You, do not torment me.” For He had commanded the unclean spirit to come out of the man. For it had seized him many times; and he was bound with chains and shackles and kept under guard, and yet he would break his bonds and be driven by the demon into the desert. And Jesus asked him, “What is your name?” And he said, “Legion”; for many demons had entered him. They were imploring Him not to command them to go away into the abyss. (Lk. 8:27-31 NASB)
I captured a few more verses of this passage because I wanted to make something clearer I mentioned in the first entry on this topic. This “legion” of demons was strong enough to negotiate with God the Son. In other passages where Jesus is casting out demons, there’s no discussion, no debate, no delay, they simply fly out of people when Jesus says to, and shut up when He says to. He says it, they do it. These guys resist, and resist successfully.