I was going to say they both claimed that Christians and Muslims worship and adore the same God, but that might be taken to mean that both Washington and Jefferson were "Christians," which we know, after examining the evidence and arguments for over the decade, is quite contentious.
So our American Creation co-blogger Pastor Tubbs claims the notion that Christians and Muslims don't worship the same God is "basic Christian doctrine." As I told him in the comments, I respect his position and think it's an entirely defensible argument for a traditional Christian believer to make. However, I do question just how "basic" this position is to "Christian doctrine."
There are plenty of traditionally minded small o orthodox Christians who believe Jews, Christians and Muslims worship the same God, just as there are plenty who support Pastor Tubbs' position.
America's key Founders -- the first four Presidents, Ben Franklin and a few others -- however, were firmly in the camp of believing Jews, Christians and Muslims did in fact worship the same God. Others too, unconverted Native Americans, pagan Greco-Romans and Hindus worshipped the same God as Christians.
This has been used as an argument AGAINST the "Christian America" thesis.
The theory of "natural religion" which America's key Founders endorsed held that men of all religions worshipped the same God whose existence could be detected from reason alone. And they strained to find monotheistic God worship in the what we might term polytheistic religions. Traditional Hinduism, Zeus worship was still "worshipping the same one true God" as Christians worship, but with those others, getting the details a bit wrong.
How is that possible? For one, the lines between and among monotheism, polytheism and henotheism aren't so easy to draw. The Bible doesn't speak of "One God" who is clearly distinct from everything else, but rather of a divine family with (arguably) One Chief. A Sky Father. Or Yoo Pater (Jupiter).
If there are, as the orthodox Trinitarians understand, a divine Three who are equally in charge, such has vexed much of the non-orthodox (and those trying to be orthodox) Christian world since the beginning. Worshipping a divine Three, to the Jew, Muslim and unitarian Christian raises the specter of polytheism.
After doing much meticulous research, I do not believe George Washington was an orthodox Trinitarian Christian. I do believe he was a theist who believed in an active personal God. And GW greatly supported the institution of "religion" generally (and "Christianity" as a particular of that genus).
Still, I understand, the smoking guns proving that Washington was in the personal religious belief camp of Franklin, Jefferson, and J. Adams aren't there. Washington didn't bitterly reject orthodox Trinitarian doctrine like Jefferson and Adams did or give us as much extant heterodoxy as Franklin.
In all of the over 20,000 pages of Washington's recognized public and private utterances, Jesus Christ is spoken of only one time by name and one other time by example, both in public addresses written by other people (aids and subordinates) but given under Washington's imprimatur (meaning he edited and otherwise approved of the addresses with his signature).
In one of them, GW mentions the "divine author of our blessed religion," which obviously refers to Jesus. That's the closest to a smoking gun that GW was an orthodox Trinitarian Christian. I would argue that such is consistent with Arianism, Socinianism, Mormonism, and many other things that are not orthodox Trinitarian Christianity.
But still, I would concede that statement strongly resonates with orthodox Christianity.
So if we concede that a public address written by someone who is not George Washington, but rather for him, and that was, after GW's tweaking given under the imprimatur of his signature accounts for at the very least a "joint authoring," let us look at one GW did with Thomas Jefferson.
The letter was written on March 31, 1791. It was addressed to Yazid ibn-Muhammed, the new Emperor of Morocco, whose father had just passed and Washington sent his condolences as he introduced Thomas Barclay as the new American consul.
Here is how Washington closed the letter:
“May that God, whom we both adore, bless your Imperial Majesty with long life, Health and Success, and have you always, great and magnanimous Friend, under his holy keeping.”