The day on which this took place was a Sabbath, and so the Jewish leaders said to the man who had been healed, “It is the Sabbath; the law forbids you to carry your mat.” But he replied, “The man who made me well said to me, ‘Pick up your mat and walk.’ ” So they asked him, “Who is this fellow who told you to pick it up and walk?” The man who was healed had no idea who it was, for Jesus had slipped away into the crowd that was there. Later Jesus found him at the temple and said to him, “See, you are well again. Stop sinning or something worse may happen to you.” The man went away and told the Jewish leaders that it was Jesus who had made him well.
The chap who was healed was not healed because he was a good man. Indeed he seems to be a bit of a coward. When the Pharisees catch him carrying his mat on the Sabbath he quickly passes the blame and he can't even remember who healed him. Later when he meets Jesus again he tells tales.
So much for those who believe you just need a little more faith and you will be healed. So much for those who believe healing is part of salvation. The healing here was an act of grace. Given out of compassion, not deserved, not a reward for faith. Some may have called it wasted on him. We sing a hymn "Jesus thou art all compassion..." and so he is. Grace, grace upon grace; it is never exhausted.
Jesus admonishes the man, "Stop sinning or something worse may happen to you." He emphasizes that simply healing is not enough; those who are saved must show a change in their behavior if it is genuine salvation.