In his sermon, Derek discusses the parable of the Pharisee and the publican, highlighting the contrasting attitudes of pride and humility in their prayers. The Pharisee exemplifies self-righteousness, thanking God for his perceived goodness while looking down on others, while the publican humbly acknowledges his sinfulness and pleads for mercy. Derek reminds the congregation that true righteousness is not measured by comparison to others but by recognizing one's own need for God's grace. Ultimately, he emphasizes that those who exalt themselves will be brought low, while those who humble themselves will be lifted up by God.