He is remembered especially for his great work on Christian theology, Institutes of the Christian Religion (which still exercises great influence, which every professing Protestant could profitably read and which every critic of Calvinism ought to have studied, if he wishes to be taken seriously), and for his commentaries on almost every book of the Bible. Calvin's Protestant contemporaries recognized his outstanding gifts, especially in theology and exposition of Scripture. They referred to him simply as "the Theologian."
Naaalala siyang higit sa kanyang dakilang gawa sa teyolohiyang Cristiano, ang Institutes of the Christian Religion (na may malaki pa ring impluwensya, na pakikinabangan pa ring basahin ng lahat ng nagpapahayag ng pagka-Protestante, at sana’y napag-aralan ng bawat kritiko ng Calvinism, kung nais niyang siya ay seryosohin sa kanyang mga panunuligsa), at sa kanyang mga komentaryo sa halos lahat ng aklat ng Biblia. Kinilala ng mga kasabayan ni Calvin ang kanyang mga nangingibabaw na kakayahan, lalo na sa teyolohiya at pagpapaliwanag ng Banal na Kasulatan. Simple nila siyang tinaguriang "Ang Teyologo."