In chapter 12 of de Regno Christi , Bucer’s programmatic treatise on reformation of church and state, the Reformer of Strassbourg, and mentor of Calvin, discusses “Lent and other fasts.”

He begins with a brief summary of the history of Lent, pointing out that the early church had a diversity of practices regarding fasting. He concludes that “it is anti-Christian to prescribe fasting for Christians as something per se necessary for salvation,” since Jesus and the apostles “left its observance free for Christians.”

At the same time, while condemning Catholic practices and urging young Edward VI to avoid imitating them, Bucer argued that “the Lord himself and his apostles so highly recommended fasting to the churches” that “they who observe no fasting at all cannot glory in the spirit and sovereignty of Christ.” Those who want “to see the Kingdom of Christ solidly restored” thus need “to retrieve this discipline of fasting, at least on some days of the year.” For Bucer, fasting was a tactic of Reformation, and without fasting the Reformers would not achieve their reforming aims.