Why does Paul emphasize mercy in salvation?

In Titus 3:5, Paul emphasizes that salvation is based not on our works but according to His mercy. This underscores the reality that we are entirely dependent on God's grace for our salvation. Mercy refers to god's compassion and kindness toward undeserving sinners, making it impossible for anyone to claim that they earned their salvation. It's a pivotal concept because it reflects the nature of God's saving work through Christ, showcasing His love and grace that leads to justification by faith.