Martin Luther believed that salvation is achieved through faith alone. This belief is known as "sola fide" in Latin, meaning "faith alone." It was one of the key tenets of the Protestant Reformation that Luther spearheaded in the 16th century. According to Luther, faith in Jesus Christ as the savior is the only means by which an individual can be justified and attain salvation. This belief directly contradicted the prevailing Catholic doctrine at the time, which emphasized the necessity of good works and sacraments for salvation.
