In this session of the Wednesday Summer Equip Class on the Five Solas of the Reformation, Dr. Matt Castro explores the doctrine of Sola Fide—justification by faith alone. Building on the previous lesson’s historical background, he explains the theological heart of the Reformation’s teaching that sinners are declared righteous by God’s grace through faith in Christ, apart from works or sacraments. The lesson contrasts medieval Catholic views of cooperation and merit with the Protestant insistence on faith as the sole instrument of justification. Through Scripture and Reformation history, listeners are invited to see how this doctrine preserves the sufficiency of Christ’s atoning work and the believer’s assurance of salvatio