Which theological doctrine argues for justification by faith alone, a key principle of the Reformation?

The theological doctrine that argues for justification by faith alone is known as Sola Fide. This principle emerged during the Reformation, primarily associated with Martin Luther's teachings, which emphasized that faith in Jesus Christ is the only means by which individuals are justified before God. According to Sola Fide, good works cannot earn salvation; rather, it is solely through faith that believers are made righteous in the sight of God.

This doctrine was revolutionary during the Reformation, as it challenged the prevailing beliefs of the Catholic Church, which taught that both faith and works were necessary for salvation. Sola Fide underscored the belief that salvation is a gift from God, accessible through faith, which significantly influenced Protestant theology and contributed to the major shifts in Christian practice and doctrine during the era.