In this engaging and historically rich lecture, Pastor Matthew Castro explores the historical and theological development of Sola Christus—Christ Alone—as a core doctrine of the Protestant Reformation. Focusing on the sufficiency of Christ’s atonement, the session traces how early church fathers understood the cross, highlighting key theories such as recapitulation, ransom, and penal substitution. Pastor Castro examines the shift in medieval theology that elevated the role of sacraments, penance, and the authority of the Church in applying Christ’s work to the believer. He explains how doctrines like purgatory and indulgences arose, especially through the teachings of figures like Aquinas, Anselm, and Pope Gregory the Great. The lecture also shows how cultural pressures—such as death during the Black Plague—shaped widespread fear and theological confusion, leading to the rise of practices like paying for indulgences. The session culminates in the Reformers’ bold assertion that Christ’s work is not only necessary but fully sufficient, applied to believers by grace through faith alone. Pastor Castro critiques the Catholic view of salvation as grace plus works and emphasizes the Reformation’s recovery of the gospel message: full atonement is found in Christ alone. Key Themes: Historical views of the atonement (early church to medieval period)
 Development of purgatory and indulgences
 The role of the sacraments in medieval Catholicism
 The Reformation’s defense of justification by faith in Christ alone
 The spiritual implications of union with Christ