Mark 5:18

‘And as he was entering the boat he who had been possessed with devils begged him that he might be with him. But he did not allow him, but says to him, “Go to your house, to your friends, and tell them what great things the Lord has done for you, and how he had mercy on you.”

The healed man wished to go with Jesus. But Jesus would not allow him. For what reason we can never know. Perhaps because he was a Gentile. Perhaps because he was not seen as having the background which would enable him to be a teacher. The preparation by Jesus of His disciples demanded a certain amount of pre-knowledge gained from Jewish teaching. And besides the man had had a few blank years in his life. It would take time for him to make them up. Perhaps also he could do better work for God at home. And perhaps Jesus had in mind preparation of Decapolis for when the Gospel came to them. We do not know the answer but we can be sure that Jesus had a good reason for His decision.

But He did give him a ministry. He was to go back to his home in Decapolis and tell men about ‘the Lord', and what He had done for him and how He had had compassion on him. To this man ‘the Lord' would in general be a neutral word speaking of his Lord and God (compare the designation of the Emperor), or alternately he may have known that it was the Greek Old Testament term for the God of Israel. Either way his message would be that this Lord had come from the Jews and was merciful and all-powerful. He was Lord over all the Powers of Evil. So when Jewish preachers later arrived with the message of the Gospel they would no doubt find a welcome from this man and his hearers, and ready ground prepared for their message. (Unlike the other Gospel writers, Mark does not elsewhere use ‘Lord' of Jesus).

He could allow this man to speak freely because there was no danger here in his spreading the message, for no Messiah was looked for here who could be wrongly interpreted. Nor would he draw crowds around Jesus seeking the spectacular, for Jesus was moving on.

Later, before the siege of Jerusalem, the Christians in Jerusalem would flee to Pella. This was one of the Ten Towns (Decapolis). And perhaps they too would find a more welcome reception because of this man's words.