How do we know salvation is by grace and not works?

The story of the penitent thief serves as a powerful testament to the principle that salvation is entirely by grace without any reliance on human works. This criminal, being crucified, was unable to perform any good deeds or rituals required by the Law. Despite his sinful past, all he did was express faith in Jesus, recognizing Him as Lord. His immediate assurance of paradise upon death showcases Christ's ability to save to the uttermost, emphasizing that it is God's grace that draws and saves sinners. This enables us to understand that God's mercy is not contingent on our righteousness; rather, salvation comes through faith in Christ alone, demonstrating the heart of sovereign grace theology.