This was an “election sermon” by a figure who was the President of Harvard from 1774 till 1780. The title of the sermon speaks for itself. You can read it and make up your mind on what to make of its contents. While someone like David Barton or Glenn Beck might agree with its theology and conclude it supports the accuracy of the “Christian Nationalist” view of history, others beg to differ.
I understand why a Mormon would believe in the theology of the piece, precisely because of when and where Mormonism was founded. Mormonism incorporates various eccentric late 18th Century Americanist historical dynamics into its theology. For instance, they believe as a matter of doctrine that America’s Constitution was a divinely inspired document.
Because orthodox Christianity was founded one thousand and some hundred odd years before America and thus teaches nothing special about America as a particular country, serious scholars of political theology, many of whom devoutly believe in orthodox Christianity and try to get the faith right, understand these sermons and their premises differently. I’m thinking of among others Drs. Mark Noll, Nathan Hatch, George Marsden, Robert Kraynak, Gregg Frazer and John Fea.
The notion that Ancient Israel had a “republic” that could serve as an example to the newly established “United States” is as much a creation of Whig and Enlightenment thought as it is “biblical.” And since the concept of a “republic” actually derives from the Ancient Greco-Roman tradition (for whom America’s Founders had an affinity) arguably that ideological strand gets dragged in too here.
As Dr. Frazer observes on the content of this and related sermons:
[They] 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 sovereignly determined plan. By their account, God submitted the laws to the people for their approval and acceptance (as per Rousseau’s legislator).
— Frazer, PhD thesis, pp. 393-94.