From: Matthew 8:28-34
The Demoniacs of Gadara
 And when He (Jesus) came to the other side, to the country of the Gadarenes, two demoniacs met Him coming out of the tombs, so fierce that no one could pass that way.  And behold, they cried out, "What have You to do with us, O Son of God? Have You come here to torment us before the time?"  Now a herd of many swine was feeding at some distance from them.  And the demons begged Him, "If You cast us out, send us away into the herd of swine."  And He said to them, "Go." So they came out and went into the swine; and behold, the whole herd rushed down the steep bank into the sea, and perished in the waters.  The herdsmen fled, and going into the city they told everything, and what had happened to the demoniacs.  And behold, all the city came out to meet Jesus; and when they saw Him, they begged Him to leave their neighborhood.
28. Most Gospel codexes and the New Vulgate say "Gadarenes"; but the Vulgate and parallel texts in Mark and Luke have "Gerasenes". Both names are possible; the two main towns in the area were Gerasa and Gadara. The event reported here could have happened close to both towns (limits were not very well-defined), though the swine running down into the lake or sea of Galilee makes Gadara somewhat more likely. "Gergesenes" was a suggestion put forward by Origen.
28-34. In this episode Jesus once more shows His power over the devil. That it occurred in Gentile territory (Gerasa and Gadara were in the Decapolis, east of Jordan) is borne out by the fact that Jews were forbidden to raise swine, which the Law of Moses declared to be unclean. This and other instances of expulsion of demons narrated in the Gospel are referred to in the Acts of the Apostles, when St. Peter addressed Cornelius and his household: "He went about doing good and healing all that were oppressed by the devil" (Acts 10:38). It was a sign that the Kingdom of God had begun (cf. Matthew 12:28).
The attitude of local people towards this miracle reminds us that meeting God and living a Christian life require us to subordinate personal plans to God's designs. If we have a selfish or materialistic outlook we fail to appreciate the value of divine things and push God out of our lives, begging Him to go away, as these people did.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.