Protestantism did not separate money and religion. Read our confessions and catechisms and that will be quite clear. A representative example would be the [WLC](https://opc.org/lc.html) on what the 8th Commandment ("Thou shalt not steal") both prohibits and requires:
> Q. 140. Which is the eighth commandment?
> A. The eighth commandment is, Thou shalt not steal.
> Q. 141. What are the duties required in the eighth commandment?
> A. The duties required in the eighth commandment are, truth, faithfulness, and justice in contracts and commerce between man and man; rendering to every one his due; restitution of goods unlawfully detained from the right owners thereof; giving and lending freely, according to our abilities, and the necessities of others; moderation of our judgments, wills, and affections concerning worldly goods; a provident care and study to get, keep, use, and dispose these things which are necessary and convenient for the sustentation of our nature, and suitable to our condition; a lawful calling, and diligence in it; frugality; avoiding unnecessary lawsuits, and suretiship, or other like engagements; and an endeavor, by all just and lawful means, to procure, preserve, and further the wealth and outward estate of others, as well as our own.
> Q. 142. What are the sins forbidden in the eighth commandment?
> A. The sins forbidden in the eighth commandment, besides the neglect of the duties required, are, theft, robbery, man-stealing, and receiving anything that is stolen; fraudulent dealing, false weights and measures, removing landmarks, injustice and unfaithfulness in contracts between man and man, or in matters of trust; oppression, extortion, usury, bribery, vexatious lawsuits, unjust enclosures and depredation; engrossing commodities to enhance the price; unlawful callings, and all other unjust or sinful ways of taking or withholding from our neighbor what belongs to him, or of enriching ourselves; covetousness; inordinate prizing and affecting worldly goods; distrustful and distracting cares and studies in getting, keeping, and using them; envying at the prosperity of others; as likewise idleness, prodigality, wasteful gaming; and all other ways whereby we do unduly prejudice our own outward estate, and defrauding ourselves of the due use and comfort of that estate which God hath given us.
Didn't John Calvin permit interest on commercial loans and thereby abolish the usury doctrine against mutuum?
The Swiss Reformers thereby normalized the business of making money off of money, and became the financial engine of all Protestant countries, where the state strengthened over the church, in order to help the money lenders collect their profits?
This source claims the Reformers were originally all against making money off of money, upholding the medieval scholastic tradition, and then Calvin broke ranks and it just cascaded from there and eventually was also adopted by the Catholic Church.
It's more complex than that - see Vol I of Rothbard's [Austrian Perspective on the History of Economic Thought](https://mises.org/library/book/austrian-perspective-history-economic-thought). I would lay the fault of our credit-driven economies largely at the feet of Peel's Laws in the mid 1800s, the advent / rise of Fractional Reserve Banking--the rise of the social-gospelers like Rockefeller, and the Rothschilds, etc. and all the State paternalism that that implied.
But either way, the Reformers always taught that the moral law of God frames all activities, commerce not excluded, so I don't see how they can be accused of "separating money and religion." Interest is a necessary function of functioning economies, as all the 'Austrians' ably show.
If I may: question the sources (like Brad S. Gregory) that lay the guilt of all modern problems at the feet of the Protestant Reformers. The Protestant Reformers, in particular, were implementing (though slowly) the principles we know as "classical liberalism" two centuries prior to the American founders (see John Witte, Jr. [The Reformation of Rights: Law, Religion and Human Rights in Early Modern Calvinism](https://www.amazon.com/Reformation-Rights-Religion-Modern-Calvinism/dp/0521521610/ref=sr_1_1?s=books&sr=1-1)).
Regarding that last comment about Brad Gregory see [this review](https://www.thegospelcoalition.org/reviews/the-unintended-reformation/) by Michael Horton.
