Were the Founding Fathers Deists?
The general Principles, on which the [founding] Fathers Achieved Independence, were the only Principles in which that beautiful Assembly of young Gentlemen could Unite, and these Principles only could be intended by them in their Address, or by me in my Answer. And what were these general Principles? I answer, the general Principles of Christianity, in which all those Sects were united: . . . Now I will avow, that I then believed, and now believe, that those general Principles of Christianity, are as eternal and immutable, as the Existence and Attributes of God; and that those Principles of Liberty, are as unalterable as human Nature and our terrestrial, mundane System.
Source: An article by Gary Demar at AmericanVision.org. Gary Demar listed the source as “John Adams to Thomas Jefferson, June 28th, 1813. Lester J. Cappon, ed., The Adams-Jefferson Letters: The Complete Correspondence Between Thomas Jefferson and Abigail and John Adams (Chapel Hill, NC: The University of North Carolina Press, 1988), 338–340.”