Pharisees were severely criticised by Jesus in the gospels. They meticulously kept the law but in doing flaunted their righteousness - like the one in today’s parable - and despised those they regarded as sinners. In doing this they became their own gods. By behaving this way they failed to fulfill their potential. A pharisee like Paul, who learnt humility through his love of Jesus, made an enormous contribution to the conversion of the gentiles, which he was uniquely equipped to do. We too benefit by his learning amd insights, from the numerous letters that he wrote.
The tax collector was aware of his own sinfulness and asked for mercy. He too, however, was failing to reach his potential, by continuing to work for the Romans and cheating his own people. He had taken the first step by acknowledging his need for God but he needed to change, like Zacchaeus, who - encountering the love and forgiveness of the Lord - vowed to make reparation for the harm he had done (Luke 19:1-10).
Perhaps in all of us is a pharisee and tax collector. There is a great temptation to see oneself as better than others, especially the weak and the flawed, and a difficulty in making the changes that will enable us to reach our full potential. We must realise that we are all sinners, loved and redeemed.