I thought that blogger Jon Rowe, in his response to “Christian Stoics and Skeptical Christians,” made an excellent point. “Let me point something else out—what I think is a non-sequitur—which I’ve noticed folks who argue from Mr. Novak’s side often engage in,” he says. “The argument goes something like this: Analyze a particular phrase uttered from a Founder; find some way in which that phrase traces back to the Bible; and then conclude this warrants placing the Founder in the ‘orthodox / Christian / religious’ box or what have you.” This is absolutely true. All of us have been indelibly stamped by the Bible, whether we are believers or not. This was much more true in the 18th century; the Founders all grew up in an intensely biblical culture. As Rowe points out, even the violently anti-Christian and anti-clerical Thomas Paine made biblical allusions.
As I noted in the original comment, whatever the Biblical allusions Washington may have made, Franklin and Jefferson -- whom Novak identifies as "outliers, skeptics indeed, barely if at all Christian” -- knew the Bible probably better than Washington and alluded to it as much as he did.
As also noted, the Bible, especially as a piece of literature, has dramatically impacted Western Civilization. I’ve described, on my blogs, (after Camille Paglia) Western Culture itself as a unique synthesis of Paganism (Greco-Romanism) and Piety(Judeo-Christianity). Indeed Christmas and Easter, both of which have pagan and traditional religious elements, perfect illustrate such dynamic. We can endlessly analyze how various parts of our culture trace back in some way to our religious (for instance, the way we date our time) or pagan (the names of the days of the week, months of the year, or planets in our solar system) roots.
To give a personal anecdote, I once debated, in an Internet forum, some cultural issue, where I was on the more secular liberal side. I think it had to do with gay rights. When saying good bye to a fellow debater on my side, I replied “keep fighting the good fight.” Someone on the opposing side, a traditional Christian who really didn’t like me that much, became angry that I said this because that phrase traces back to the Bible.
Indeed, when I teach at my secular community college, I notice myself making Biblical allusions all the time. The Bible has so dramatically impacted our language that common people make Biblical allusions all the time without being aware of their so doing. This is especially the case for more literate, well-educated folks (who arguably tend to be less religious than average).
Lincoln too, certainly no orthodox Christian, notably used Biblical allusions (e.g. "A house divided against itself cannot stand"). Though it may be an interesting literary study to analyze a Founders' or anyone's words and see how certain phrases trace back to the Bible, how certain phrases trace back to Shakespeare, etc. etc., such tells us absolutely nothing about the orthodoxy of their personal religious beliefs.