The Church had always been uncompromisingly against usury as a matter of moral rivalry

All of this helps explain why the Church had been so uncompromising in its attitude toward usury. It was not just a philosophical question; it was a matter of moral rivalry.

Money always has the potential to become a moral imperative unto itself. Allow it to expand and it can quickly become a morality so imperative that all others seem frivolous in comparison.

This is one of the many passages and charts I find in books and articles on a daily basis. They span many disciplines, including:

I occasionally add a personal note to them.

The whole collection is available here.