Of all the dispositions and habits which lead to political prosperity, religion and morality are indispensable supports....And let us with caution indulge the supposition that morality can be maintained without religion. Whatever may be conceded to the influence of refined education on minds of peculiar structure, reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.
Now, this certainly provides ammo for those who wish to "lower" the wall of separation between Church and State; however, I see it oft-cited in order to prove the "Christian Nation" claim or Washington's orthodox Christianity. And it does neither. Arguably it expresses a heterodox unitarian sentiment.
First Washington's Farewell Address never specifies "Christianity" or "orthodox Christianity" as *the* religion that must support republican government. Although that kind of "religion" certainly would, as Washington's theory goes, suffice. And second its view of religion is entirely instrumental, utilitarian or "civil." What can religion do for government? And here is where we stumble upon the biggest disconnect between orthodox Christianity and George Washington's heterodox sentiments in his Farewell Address.
Orthodox Christians believe that the primary purpose of religion is to save souls, not necessarily make men moral and hence self-governable. And it's through Christ's blood atonement alone that men are saved. It's true that one can believe in both [my religion a) not only saves souls, but also b) provides wonderful civil utility in the way it makes men moral]. However, it seems to me that any serious orthodox Christian who really does believe that men are saved through Christ's blood atonement as the ONLY way to God would prioritize salvation over civil utility. And this is something that Washington NEVER did, even in his correspondence with the orthodox clergy where they seemed to talk past one another. Washington rarely if ever intimated to them that Christ was the only way to God and thanked them for saving men's souls (as you would expect him to do were he an orthodox Christian). Rather he invariably thanked them for making men moral and consequently supporting republican government.
The following from Washington praising Presbyterian Clergy is typical of his sentiment:
While I reiterate the professions of my dependence upon Heaven as the source of all public and private blessings; I will observe that the general prevalence of piety; philanthropy, honesty, industry, and economy seems, in the ordinary course of human affairs, particularly necessary for advancing and conforming the happiness of our country. While all men within our territories and protected in worshipping the Deity according to the dictates of their consciences; it is rationally to be expected from them in return, that they will be emulous of evincing the sanctity of their professions by the innocence of their lives and the beneficence of their actions; for no man, who is profligate in his morals, or a bad member of the civil community, can possibly be a true Christian, or a credit to his own religious society.
I desire you to accept my acknowledgments for your laudable endeavors to render men sober, honest, and good Citizens, and the obedient subjects of a lawful government.
Washington's praise for the clergy is all about civil utility. And because of their belief in the civil utility of religion, the key Founders elevated works over faith as more important towards salvation. As the theory goes, "sound" religion, in fact produces the virtue which supports republican government. And they found "sound religion" in, at the very least, Christianity, Deism, Unitarianism, Judaism, Islam, Hinduism, Native American Spirituality, and Pagan Ancient Greco-Roman worship.
Here are some quotations of the Founders expressing this heterodox notion that works are more important than faith:
"My fundamental principle would be the reverse of Calvin's, that we are to be saved by our good works which are within our power, and not by our faith which is not within our power."
-- Thomas Jefferson to Thomas B. Parker, May 15, 1819.
"No point of Faith is so plain, as that Morality is our Duty; for all Sides agree in that. A virtuous Heretick shall be saved before a wicked Christian."
-- Benjamin Franklin, "Dialogue between Two Presbyterians," April 10, 1735.
"Faith is recommended as a Means of producing Morality: Our Saviour was a Teacher of Morality or Virtue, and they that were deficient and desired to be taught, ought first to believe in him as an able and faithful Teacher. Thus Faith would be a Means of producing Morality, and Morality of Salvation. But that from such Faith alone Salvation may be expected, appears to me to be neither a Christian Doctrine nor a reasonable one....Morality or Virtue is the End, Faith only a Means to obtain that End: And if the End be obtained, it is no matter by what Means."
Franklin's logic is quite clear: If non-Christian religions produce virtue in people, then those "good people" are saved via their works. So the primary aim of Christianity and all other religions is to produce good people. Christians might have some special advantage over the other world religions in that Jesus of Nazareth, our key Founders believed, was a great, arguably the greatest moral teacher. Thus, Christians' best hope for salvation was to follow his teachings and example.
Next, J. Adams on the true purpose of Christianity:
"...the design of Christianity was not to make men good Riddle Solvers or good mystery mongers, but good men, good magestrates and good Subjects...."
-- John Adams, Dairy, Feb. 18, 1756
In this letter to James Fishback, Sept. 27, 1809, Jefferson connects religion with morality, just as Washington did, but further specifies that all world religions produce such morality:
Every religion consists of moral precepts, and of dogmas. In the first they all agree. All forbid us to murder, steal, plunder, bear false witness &ca. and these are the articles necessary for the preservation of order, justice, and happiness in society. In their particular dogmas all differ; no two professing the same. These respect vestments, ceremonies, physical opinions, and metaphysical speculations, totally unconnected with morality, and unimportant to the legitimate objects of society. Yet these are the questions on which have hung the bitter schisms of Nazarenes, Socinians, Arians, Athanasians in former times, and now of Trinitarians, Unitarians, Catholics, Lutherans, Calvinists, Methodists, Baptists, Quakers &c. Among the Mahometans we are told that thousands fell victims to the dispute whether the first or second toe of Mahomet was longest; and what blood, how many human lives have the words 'this do in remembrance of me' cost the Christian world!...We see good men in all religions, and as many in one as another. It is then a matter of principle with me to avoid disturbing the tranquility of others by the expression of any opinion on the [unimportant points] innocent questions on which we schismatize, and think it enough to hold fast to those moral precepts which are of the essence of Christianity, and of all other religions.
Through this perspective, go back and reread Washington's Farewell Address and see not only does it perfectly fit with the above quoted beliefs of Adams, Franklin, and Jefferson (indeed the Address was written by Hamilton, who like them was a theistic rationalist, not a Christian), arguably it resonates more with such heterodox belief system than with orthodox Christianity (even ultimately, it if was consistent with both belief systems). Washington never said one need be Christian in order to be saved but rather that religion is necessary for morality. Washington's Address represented a brilliant use of abstractions where he could express his heterodoxy in a way which seemed consistent with the prevailing orthodoxy of the day, yet still not outright lie.