How do you feel about yourself, or better yet, what is your self-image? It is one thing to be proud of our accomplishments before men, but it is totally different to boast before God? In the eyes of people, the Pharisee might have been a good man, morally and ethically superior to the tax-collector, but this was not the case before God. We stand before God, not as self-righteous people but as sinners in need of His grace.
1 Corinthians 1:26-31 (Boast in the Lord!)
Luke 18:9-14 (The Pharisee and the Tax Collector)