NOTES for Luk 18:9-14
The tax collector and the Pharisee are two sides of a person that coexist peacefully within us. At the same time, the Pharisee living in us can be a very worthy person: fasting, prayer, a tithe of everything one has. This is already not so little.
Even the Lord says that "this man went down to his house justified rather than the other." That is, the Pharisee received his justification, but not to the same extent as the tax collector. This happened because the Pharisee demanded fair treatment for himself, while the tax collector hoped for mercy.
In the end, we too need not justice, whose triumph the Pharisee within us wants so often; we need mercy, for which the tax collector quietly asks. For according to justice we are entitled to very little, if not to nothing at all, while according to mercy the Kingdom has been promised to us.