This passage from Gregg Frazer's thesis made an impression on me when I first read it. He discusses some of the sermons from America's founding era that argued on behalf of the patriots' cause. These particular sermons preached the Bible taught "republicanism." (When "republicanism" arguably is entirely a creation of ancient Greco-Romanism.)
The sermons seem to depict God's role as something similar to Rousseau's legislator; He disinterestedly established the foundational law for the benefit of society, but did not live under it. In their version and consistent with democratic theory, God established it all [quoting Langdon's sermon] "for their happiness" rather than to achieve the fulfillment of a sovereignty determined plan. By their account, God submitted the laws to the people for their approval and acceptance (as per Rousseau's legislator).This was on page 393-94 of his thesis and then was adapted in his fine book and featured on pages 100-01. The conclusion that Dr. Frazer draws is that this notion that the Hebrew's had a "republic" is a more modern Enlightenment notion than a traditionally orthodox biblical understanding. Certainly, attaching Rousseau's name in a comparison illustrates this point.
Though Samuel Langdon, whose sermon was entitled "The Republic of The Israelites An Example To The American States," and was an American minister during the Founding era, actually drew from a prior European tradition. One you can read about in Eric Nelson's also fine book on the matter.
What does this have to do with Rousseau? Arguably something meaningful. The Hebraic republicans about whom Nelson writes -- beginning with Petrus Cunaeus and also finding expression in figures America's founders more explicitly cited like James Harrington -- argued that the Hebrew Republic had an agrarian law that limited wealth and demanded redistribution.
Whether the early exponents of the "Hebrew Republic" were traditional Christians or more philosophically minded thinkers using Christian theology as a fig leaf is debatable; but they ended up influencing later figures who tend to be understood as more modern philosophical types. Including Montesquieu, Rousseau and Thomas Paine.
As Dr. Nelson writes on page 86 of his aforementioned book:
It is a measure of Harrington’s remarkable influence that, from 1660 onwards, agrarian laws would remain permanently at the center of republican political thought. Writers from Montesquieu to Rousseau, and from Jefferson to Tocqueville, would regard it as axiomatic that republics ought to legislate limits on private ownership in order to realize a particular vision of civic life. Before Cunaeus and Harrington, European political theory had been dominated by the unequal contest between two views of property: one which saw the protection of private property as the central obligation of the state, and another which saw the abolition of private property as the ultimate salvation of mankind. Cunaeus’s innocuous semantic move in 1617 had opened up a “third way”—one which remains central to modern political thought and practice.
I can't do justice to Nelson's entire book here. He mentions that Harrington put forth both a biblical and a more secular Platonic justification for Agrarian limits on wealth and consequent redistribution. It could be that the later more secular thinkers who argued for economic leveling picked up the more Platonic and left behind the biblical.
But even someone like Thomas Paine, who by the way, I think is more clearly in the "agrarian-redistribution" camp than Jefferson, would use these biblical arguments and was clearly influenced by them.
I could be wrong about Jefferson; if I understand Madison's Federalists 10 correctly, it rejects this "republican agrarian" vision of property in favor of something more "liberal" (for the era). Jefferson may very well have signed onto Madison's vision here. (But how to properly understand Federalist 10 will be a topic for another post.)
But I hope I demonstrated in this post how someone like Rousseau didn't just invent his egalitarian speak for the modern era. The conversation had been taking place for some time. And the thinkers who preceded Rousseau attempted to make serious biblical, "republican" arguments for the economic leveling by ascribing to the Hebraic republic an agrarian law.
(Personally, I don't find the argument convincing; I don't think the Ancient Israelites had either a "republic" or that the "Jubilee" constituted an "agrarian law" that should be models for later subsequent republics. But that's neither here nor there.)