Final answer:
One of Luther's main beliefs was that faith alone was sufficient for salvation and that humans were unable to work towards their own redemption, which greatly influenced Calvin.
Step-by-step explanation:
One of Luther's main beliefs was that faith alone was sufficient for salvation and that humans were unable to work towards their own redemption, which depended entirely upon God. He also believed that scripture alone should be the source of Christian belief and practice, rejecting many traditional Catholic practices. These beliefs of Luther's, particularly the emphasis on faith alone for salvation, greatly influenced John Calvin and his development of Calvinism.