In The Protestant Work Ethic and the Spirit of Capitalism (1905), Max Weber poses the question Why is it that capitalism is most successful in Protestant nations?
Weber argues that this happens, because the religious doctrines of Protestantism, especially from the sect of Calvinism, compliment the economic principles of capitalism. For example, the Calvinist doctrine of predestination -the idea that salvation is predetermine before you are born and thus cannot be influenced by any good works on earth- made people uneasy.
People found a way to cope by assuring themselves and others that they were part of the elect few who had salvation. They showed this by accumulating wealth. Having wealth could be viewed as an outward sign that a person had God’s favor, and thus were saved. Thus, capitalism and Protestantism were compatible principles. Check out Weber’s work to see the full depth of his compelling theory.
In applying Weber’s principles today, one can see the remnants of the match between capitalism and Protestantism in the Republican party of the U.S., which tends to be associated with Protestantism and tends advocate for economic policies that favor capitalism.