Which is easier, to say, Thy sins be forgiven thee; or to say, Rise up and walk?

What does Jesus mean when he said to the Pharisees (Luke 5:23, Mark 2:9, Matt. 9:5) "Whether is easier, to say, Thy sins be forgiven thee; or to say, Rise up and walk?" Why was Jesus comparing these two phrases? Was it because they were equivalent? According to the Pharisees' doctrine, in a logical extension of it, they in fact were equivalent statements. By their own doctrinal assumptions therefore, by healing the man with palsy, Jesus showed to their face that he is Lord. In addition to this, we also look at verses in Matt. chapter 23 where Jesus uses the Pharisaic doctrine against them.