As we might expect, the news of this incredible event spread. The liberation of this man from Legion should have brought joy to all, but instead "they began to plead with Him to depart from their region" (Mark 5:17). They are afraid, perhaps of Jesus' great power or perhaps that more "economic misfortune" would befall them if He stayed. These people failed to see the wonderful compassion that Jesus has manifested! They were blind to the blessings that Jesus could bestow upon them.
Jesus granted their request and prepared to depart. The man who had been demon-possessed begged Jesus to take him along. As a frightened child awakened from a horrible dream clings to a parent, so this man clung to Jesus. Certainly he felt safe in Jesus' presence and perhaps feared that Legion might return. It is even more likely that he wanted to show his gratitude and love to His deliverer by serving Him. Undoubtedly, he also felt ashamed at the behavior of his countrymen.
Jesus, with great wisdom, denied the man's request and instead instructed him - "Go home to your friends, and tell them what great things the Lord has done for you, and how He has had compassion on you" (Mark 5:19). Thus, Jesus departed that area but left behind a witness whose very body was a living monument that testified of the Lord's compassion and power. There was a wide field of usefulness for that man, particularly in that region. His countrymen and friends, who had known him in such a deplorable condition, could now see him restored!
Some have wondered why Jesus instructed this man to spread the word of this miracle when usually He commanded that no one be told of such matters (e.g., Mark 1:44; 7:36; 8:26). The answer lies in the simple fact that Jesus was leaving the region. The primary (and perhaps only) proof of His power in that area was this man, and his story could be proclaimed freely without the possibility of an excited multitude swarming Jesus for miraculous cures. Jesus' miracles showed His compassion and power, but more importantly they attested to the fact that His message was from God. Jesus' mission was to seek and save the lost (Luke 19:10). However, it became difficult for Jesus to accomplish this goal when the multitudes became obsessed with miracles instead of His teachings. Therefore, Jesus often commanded those He healed to keep it to themselves. Such was not an issue in this situation however.
Those who heard the story of this formerly possessed man "marveled" (Mark 5:20). The record doesn't indicate if any were caused to believe on Jesus or glorify God, but certainly the message this man proclaimed laid the foundation for acceptance of subsequent preaching of the gospel in that region (cf. Mark 7:31-37).
We should marvel today that this man went from being a demoniac to an evangelist. What a wonderful transformation! Friends, all Christians today need to be evangelistic. We need to have a spirit "possessed" by the Lord's will! We need to tell our friends what great things the Lord has done for us and the compassion He has had on us! If we fail to do this, it very well might indicate that the devil has "possessed" us via one of his tools (e.g., laziness, lack of compassion, materialistic focus, fear, etc.).