In this episode, Dr. Matt Castro explores the rich historical and theological development of the doctrine of Sola Gratia—Grace Alone. Tracing the theme of grace from Scripture through the early church, Augustine, Aquinas, and into the Reformation, this lesson highlights grace as God's sovereign response to human sin. From Augustine’s Confessions to Luther’s rediscovery of grace in Romans, the episode emphasizes that salvation is not earned but entirely a gift from God. Listeners will come away with a deeper understanding of why grace is foundational to Christian identity, assurance, and transformation.