What approach did John Calvin take in his teachings that gained him followers?

John Calvin's teachings were characterized by the doctrine of predestination, which posits that God has already chosen who will be saved and who will be damned, independent of any actions or decisions made by individuals. This perspective created a framework that appealed to many followers during the Reformation. It emphasized the sovereignty of God and encouraged believers to live a life of moral rigor and discipline, reflecting their newfound faith in a predetermined salvation.

Calvin's ideas resonated with those seeking a deeper understanding of divine grace and assurance of salvation, which stood in contrast to the teachings of the Roman Catholic Church that emphasized free will and the necessity of good works for salvation. Through his writings, notably the "Institutes of the Christian Religion," Calvin established a theologically rich and organized structure that drew many to his interpretation of Christianity, thus amplifying the impact of the Reformation in Europe.