Anyone who’s puzzled by the current “Prosperity Gospel” should read The Protestant Ethic and the Spirit of Capitalism by Max Weber, or at least be familiar with it. Kenneth Copeland, Joel Osteen, and others who preach bluntly that God wants you to be rich are not making up their beliefs in a vacuum. They are building on a foundation laid by European Calvinism and the Puritanism of the American colonists.
Weber explains the bridge between medieval Catholic monastic vocation and the Protestant work ethic which saw prosperity as evidence of God’s blessing on thrift and industry.
Or, for folks not interested in an admittedly stiff read, Wikipedia’s summary is pretty good.