How do we know that God's mercy is unearned?

Scripture emphasizes that no one can earn God's mercy through their actions or righteousness. Romans 3:10-12 states, 'There is none righteous, no, not one; there is none that understandeth, there is none that seeketh after God.' This underscores that all humans are inherently sinful and incapable of seeking God without His intervention and the working of the Holy Spirit. It is, therefore, by God's sovereign choice that mercy is extended to those who humble themselves before Him. The publican's cry for mercy is a model for how God works, revealing that He chooses whom to have mercy on, independently of human merit.