What does Mark 5:17 mean?

Townspeople and farmers from the Gentile side of the Sea of Galilee have rushed to the water's edge on the word of some pig herders who report miraculous things. They arrive to find the local madman clothed and in his right mind and a herd of two thousand pigs lost to the sea. Instead of standing in awe at the transformation of their countryman, they find the source of power of these miracles and beg that He leave (Mark 5:1–16).

The word "beg" is taken from the Greek root word parakaleo which is often used in people's encounters with Jesus. The leper begged Jesus to heal him (Mark 1:40). The legion of demons begged Jesus to allow them to enter the swine and not to send them to the abyss (Mark 5:10–12). Soon, the formerly-possessed man will beg Jesus to stay with Him (Mark 5:18), and a synagogue leader will beg Jesus to heal his daughter (Mark 5:23).

Now, the people beg Jesus to leave. They had driven the possessed man out of the town, forcing him to live among tombs, but they are more comfortable with the evil they know than the power they can't control. This will soon change. In Mark 7:31–37, Jesus returns to the Decapolis area, after having told the demoniac to spread the news of God's gracious healing (Mark 5:19). This time, the people will beg Jesus for His healing touch.

If the demons had left right away without arguing about where they were to go, and if they had not entered the pigs and impelled them to mass suicide (Mark 5:1–13), the man probably would have continued on with his life with much thankfulness but likely little fanfare. Although the people are afraid of Jesus, what they witness seems to nestle into their hearts, slowly developing into acceptance and then a warm reception. This is the prevenient grace of God that works in all our rebellious hearts before we accept Him.