Two prominent figures of the Protestant Reformation movement, Martin Luther and John Calvin, had the following views on work that were somewhat different from traditional Catholic church's:
Martin Luther believed that people could serve God through their work, that the professions were useful, that work was the universal base of society and the cause of differing social classes, and that a person should work diligently in their own occupation and should not try to change from the profession to which he was born. To do so would be to go against God's laws since God assigned each person to his own place in the social hierarchy. The major point at which Luther differed from the medieval concept of work was regarding the superiority of one form of work over another. Luther, being a former priest himself, regarded the monastic and contemplative life, held up as the ideal during the middle ages, as an egotistic and unaffectionate exercise on the part of the monks, and he accused them of evading their duty to their neighbors. For Luther, a person's vocation was equated as his calling, but all calling's were of equal spiritual dignity.
Luther still did not pave the way for a profit-oriented economic system because he disapproved of commerce as an occupation. From his perspective, commerce did not involve any real work. Luther also believed that each person should earn an income which would meet his basic needs, but to accumulate or horde wealth was sinful.
According to Max Weber, an early 20th century German political economist/sociologist who coined the term "Protestant work ethic", it was John Calvin who introduced the theological doctrines which combined with those of Martin Luther to form a significant new attitude toward work. Calvin was a French theologian whose concept of predestination was revolutionary. Central to Calvinist belief was the Elect, those persons chosen by God to inherit eternal life. All other people were damned and nothing could change that since God was unchanging. While it was impossible to know for certain whether a person was one of the Elect, one could have a sense of it based on his own personal encounters with God. Outwardly the only evidence was in the person's daily life and deeds, and success in one's worldly endeavors was a sign of possible inclusion as one of the Elect. A person who was indifferent and displayed idleness was most certainly one of the damned, but a person who was active, austere, and hard-working gave evidence to himself and to others that he was one of God's chosen ones.
Calvin taught that all men must work, even the rich, because to work was the will of God. It was the duty of men to serve as God's instruments here on earth, to reshape the world in the fashion of the Kingdom of God, and to become a part of the continuing process of His creation. Men were not to lust after wealth, possessions, or easy living, but were to reinvest the profits of their labor into financing further ventures. Earnings were thus to be reinvested over and over again, ad infinitum, or to the end of time. Using profits to help others rise from a lesser level of subsistence violated God's will since persons could only demonstrate that they were among the Elect through their own labor.
Selection of an occupation and pursuing it to achieve the greatest profit possible was considered by Calvinists to be a religious duty. Not only condoning, but encouraging the pursuit of unlimited profit was a radical departure from the Christian beliefs of the middle ages. In addition, unlike Luther, Calvin considered it appropriate to seek an occupation which would provide the greatest earnings possible. If that meant abandoning the family trade or profession, the change was not only allowed, but it was considered to be one's religious duty.
In sum, the combined theological teachings of Luther and Calvin encouraged work in a chosen occupation with an attitude of service to God, viewed work as a calling and avoided placing greater spiritual dignity on one job than another, approved of working diligently to achieve maximum profits, required reinvestment of profits back into one's business, allowed a person to change from the craft or profession of his father, and associated success in one's work with the likelihood of being one of God's Elect.
