In 1518, Ulrich Zwingli was chosen to be a canon of the Zurich Cathedral, which was the beginning of his active work in the Reformation. Zwingli began from the pulpit a revolutionary series of sermons from which the New Testament alone was drawn in entirety, interpreting Scripture in its own terms independent of church tradition. This was a challenge to the Catholic Church, which had historically dominated the monopoly of interpreting the Bible. Zwingli believed that all Christians, guided by the Holy Spirit, could interpret and apply Scripture to their own lives without clergy interference.

Zwingli’s sermons were deeply influenced by Erasmus’ belief that the heart of Christianity lay in emulating the life and teachings of Christ as depicted in the Bible. Yet, as Zwingli’s theology evolved, he began to see the Bible as more than a spiritual guide. He viewed Scripture as a powerful tool for societal reform, capable of shaping not only personal morality but also political and social structures. His vision of reform extended beyond the church, advocating for changes in governance and public life that aligned with biblical principles. This holistic view of Scripture’s role laid the foundation for Zwingli’s broader reform efforts, which would eventually transform Zurich into a hub of Protestant thought and practice.