This quote has had wide circulation for decades and can be traced back to an 1860 work by John Wingate Thornton, The Pulpit of the American Revolution, which reprinted a number of sermons preached during the Revolution. In the overview of that work, Thornton explained:The church polity [form of government] of New England begat like principles in the state. The pew and the pulpit had been educated to self-government. They were accustomed “TO CONSIDER.” The highest glory of the American Revolution, said John Quincy Adams, was this: it connected, in one indissoluble bond, the principles of civil government with the principles of Christianity. 33
Thornton, an attorney and historian, grew up during the lifetime of John Quincy Adams and held many interests in common with him. His above statement in connection with Adams is Thornton's summation of part of a lengthy speech delivered by John Quincy Adams during an 1837 Fourth of July celebration at Newburyport, Massachusetts (a speech which Thornton may well have heard in person, but which he certainly later read).
In that address, Adams observed that Christmas and the Fourth of July were the two most-celebrated holidays in America, and that both were interrelated.
As Adams began his speech, he queried:
"Why is it that, next to the birth day of the Saviour of the World, your most joyous and most venerated festival returns on this day [July 4th]? . . . Is it not that, in the chain of human events, the birthday of the nation is indissolubly linked with the birth-day of the Saviour?"
"That it forms a leading event in the progress of the gospel dispensation? Is it not that the Declaration of Independence first organized the social compact on the foundation of the Redeemer's mission upon earth? That it laid the corner stone of human government upon the first precepts of Christianity. . ? 34
Comparing Adams' original 1837 exact quotation with Thornton's 1860 summary of the quote, one immediately sees the similarities. Significantly, in his 1860 work, Thornton accurately related the essence of Adams' message and never presented that phrase as being an exact quotation from Adams;
nevertheless, those who used Thornton's work in subsequent generations and writings incorrectly cited Thornton's summary as if it were a direct quotation from John Quincy Adams. Therefore, the "unconfirmed" quote attributed to Adams can be replaced with his exact quotation given above from his 1837 speech.