This is a good question for those who have not studied all the accounts, but it is easy to answer. The story about the men possessed by demons (demoniacs) in the region of Gadarenes is mentioned in all three synoptic gospels. The gospel of Matthew devotes only 6 verses to it and briefly describes the incident before moving on to the miracle where Jesus heals the paralysed man. The gospel of Mark told the same story with extra details and dedicated 20 verses to the incident, and the gospel of Luke gave an identical account to the gospel of Mark in 16 verses. This is how the story went:
Jesus and His disciples just came off the boat after He had calmed the storm in the region of Gadarenes. They were approached by two men who were possessed by demons and lived among the tombs because they were so violent that the townspeople kicked them out of town (Matt 8:28; Mark 5:1-3; Luke 8:26–27). Matthew mentioned both men, while Mark and Luke only mentioned the one who played a bigger role later in the story.
When the demons recognised Jesus, they challenged Him, saying, “What do you want with me, Jesus, Son of the Most High God? I beg you, don’t torture me!” (Matt 8:29; Mark 5:7; Luke 8:28). Jesus discerned that one of the men had many demons possessing him at once, and Jesus addressed the demons and asked what their names were. “My name is Legion,” he replied, “for we are many.” (Mark 5:9; Luke 8:30). Note that Matthew didn’t mention this part.
The demons were terrified and begged Jesus to send them into the pigs that were nearby after forcing them out of the men. He did so, and then all the pigs ran off the side of the lake’s steep bank and drowned (Matt 8:31–32; Mark 5:12–13; Luke 8:32–33). The people tending to the pigs were freaked out and ran into town and told everyone what had happened. The townspeople rushed to the site and begged Jesus and His disciples to leave (Matt 8:33:34; Mark 5:14–17; Luke 8:34–37).
At this point, Matthew decided to move on to the next miracle and did not mention the incident that occurred next.
One of the men, the one who had the legion of demons inside him (and the only one that Mark and Luke mention), ran to the boat that Jesus and His disciples were getting into and begged Him to allow him to travel with them. But Jesus said no; he was to go out and tell everyone he could about what Jesus had done for him (Mark 5:18–20; Luke 8:38–39).
And that’s it. There’s no contradiction, just a case of one author telling what he felt were the most important aspects as an eyewitness to the incident. Mark and Luke interviewed the other witnesses and decided to report the incident in more detail, not just a summary. Their focus on only one of the two men is understandable, as he adds more to the story.
You can find more articles dealing with the alleged contradictions in the Bible at the link below:
