How did Calvin's ideas differ from Luther's?

Calvin's ideas differed from Luther's primarily in their views on predestination and the Eucharist.

John Calvin and Martin Luther were two of the most influential figures of the Protestant Reformation, but their theological ideas were not identical. One of the main differences between them was their views on predestination. Calvin, a French theologian and pastor, believed in absolute predestination, which is the idea that God has already decided who will achieve salvation and who will not. This belief is often summarised as 'once saved, always saved'. Calvin argued that humans are inherently sinful and can only be saved by God's grace, not by their own actions or merits.

On the other hand, Luther, a German monk and theologian, held a different view. He believed in 'single predestination', which means that God predestines some people to salvation, but does not predestine others to damnation. Instead, those who are damned are so because of their own rejection of God's grace. Luther also emphasised the importance of faith in achieving salvation, arguing that faith alone, not good works, is what justifies humans before God.

Another significant difference between Calvin and Luther was their understanding of the Eucharist, or the Lord's Supper. Calvin believed in a spiritual presence of Christ in the Eucharist. He argued that while Christ's body is in heaven, believers partake in his body and blood in a spiritual sense during the Eucharist. This view is often referred to as 'spiritual real presence'.

Luther, however, believed in 'sacramental union', also known as 'consubstantiation'. According to this view, Christ's body and blood are 'in, with, and under' the forms of bread and wine during the Eucharist. This means that Christ is truly present in a physical, though not material, sense.

In summary, while both Calvin and Luther were key figures in the Protestant Reformation and shared many theological beliefs, they differed significantly in their views on predestination and the Eucharist. These differences have had a lasting impact on the various branches of Protestantism that have developed from their teachings.