Tell people

“As Jesus was getting into the boat, the man who had been demon-possessed begged to go with Him. Jesus did not let him, but said, ‘Go home to your family and tell them how much the Lord has done for you, and how He has had mercy on you.’” Mark 5:18-19
Becoming saved is only the first step in our journey as Christians. We celebrate when we see people respond to an altar call, but we forget that this is not the end of the matter. If it was, God would take us to be with Him immediately – and there would be no witness left on earth. No, God has work for us to do after we are saved. We are to be His light in the world.
Jesus tells the man here, the same thing we should do: tell people how much the Lord has done for us, and how He had mercy on us. We might not have been delivered from demons, as this man had, but we have been delivered from a life of bondage to sin and an eternity in hell. We didn’t deserve salvation, but God reached out His hand to us anyway.
In Mark 7:31 we read how Jesus returned to the region and people came to Him. This led to the feeding of the 4000. No doubt these people heard the testimony of the man who had been demon-possessed, and wanted to see Jesus for themselves. The man was obedient, and there was fruit.