So I don’t agree with it , but it may have something to do with ‘work’ there is part of Christianity that assigns value to work and that work will be rewarded by god. They are supposed to be works of faith, but some sects of Christianity assigns value to all work.

So they see riches as a just reward from god for being hardworking and honest. They inherently see riches as a reward for good work and poverty as a punishment for lack of ethic. As well anyone can better their position and get rich by becoming more aligned with god. So bring rich is an outward manifestation of one’s reward from God.

This is a simplification and extrapolates out a bunch of things.