The entire point of the account is that Jesus proved the Pharisees were wrong when they said, "Who can forgive sins but God alone?" Jesus proved them wrong by asking them if it was easier to forgive sins or heal a man. Then he healed the man so that they might know that a human being was given authority to forgive sins by proving he had the authority to do something greater than forgive sins. The account ends at Matthew 9:8 by saying the crowd was amazed that God had given such authority to MEN.

Jesus received this authority when God anointed him in His Spirit at the Jordan River. Acts 10:38. In this way, God commissioned Jesus to do things in His name, things like forgiving sins. He did these things in the name of the Father. John 5:43. Likewise, Jesus sent out his disciples just as the Father had sent him - by anointing them with the Spirit. John 20:21-23. To see how the disciples forgave sins in Jesus' name, see Acts 2:38. This is how they were instructed to go about it.