Mark 5:9 "And [Jesus] asked him, What is thy name? And he answered, saying, My name is Legion: for we are many." (King James Version)1
The story of Jesus casting the demons out of the possessed man and into a herd of pigs is told in Mark 5:1-20, Matthew 8:28-34, and Luke 8:28-39. The Gospel according to John does not tell the story. Of the three, Mark is the one that quotes the line as it is most famously remembered. Mark is also the only one to give an estimate of the number of demons, in verse 13 (about two thousand). Matthew does not name the demons, although, like Mark, Luke calls them Legion (verse 30).
Luke (verse 26) and Mark (verse 1) agree on the name of the location (the country of the Gadarenes), but Matthew (verse 28) claims it happened in the country of the Gergesenes. These are likely just two names of the same place.2
Luke (verse 27) and Mark (verse 2-3) agree one man was possessed, but Matthew (verse 28) claims two possessed men. All authors claim the possessed were living in the tombs, and that the demons begged to be sent into the nearby herd of pigs when Jesus threatened them (see Matthew 8:29-31 below). Luke (verse 31) adds that the demons preferred this to being sent "out into the deep". All authors agree the pigs then immediately ran into a lake or the sea, and drowned, and the possessed man (or men) was cured.
This story is sometimes literally translated as a real account of demonic possession, but other times interpreted as an allegory for salvation from temptation and evil, or just an overwhelming number of problems and other suffering. The fact that there are many demons is important to this translation, because while most people can easily deal with one or two temptations, or a small number of problems in their life, it can often become overwhelming when they start multiplying out of control. The message here is that with God's help, we can overcome any difficulties, no matter how numerous.
Since Matthew's account is the shortest, I will reproduce it here (although Matthew's account does not mention the name Legion).
- And when he was come to the other side into the country of the Gergesenes, there met him two possessed with devils, coming out of the tombs, exceeding fierce, so that no man might pass by that way.
- And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time?
- And there was a good way off from them an herd of many swine feeding.
- So the devils besought him, saying, If thou cast us out, suffer us to go away into the herd of swine.
- And he said unto them, Go. And when they were come out, they went into the herd of swine: and, behold, the whole herd of swine ran violently down a steep place into the sea, and perished in the waters.
- And they that kept them fled, and went their ways into the city, and told every thing, and what was befallen to the possessed of the devils.
- And, behold, the whole city came out to meet Jesus: and when they saw him, they besought him that he would depart out of their coasts.