Jesus has just told a man his sins are forgiven. The Pharisees, knowing something about theology and realizing only God could forgive sins, quickly understood Jesus had just impliedly claimed to be God. Jesus understanding what the Pharisees were thinking, called them on it and said,
“Which is easier, to say, ‘Your sins have been forgiven you’ or to say, ‘Get up and walk’? But, so that you may know that the Son of Man has authority on earth to forgive sins–He said to the paralytic–“I say to you, get up, pick up your stretcher and go home.”
Jesus understood the Pharisees were questioning His authority to forgive sins. Authority is something you cannot see. You can see symbols of it–a badge, a uniform, a seal–but authority itself is unseen.
Jesus could have told the Pharisees to accept on blind faith that He had the authority to forgive sins. Instead, Jesus offered them something more–“But, so that you may know that the Son of Man has authority on earth to forgive sins…”–and then gave them visible, tangible evidence of His authority by healing the paralytic.
Pretty good evidence. GS