Some of these are more pertinent than others, but nearly all of them refute the illusion that the founding fathers were true christians, at least in the fundy sense:
"I am persuaded, you will permit me to observe that the path of true piety is so plain as to require but little political direction. To this consideration we ought to ascribe [credit] the absence of any regulation [law], respecting religion, from the Magna-Charta [Constitution] of our country"
George Washington, 1789, Papers, Presidential Series, 4:274
"As I understand the Christian religion, it was, and is, a revelation. But how has it happened that millions of fables, tales, legends, have been blended with both Jewish and Christian revelation that have made them the most bloody religion that ever existed?"
..........To F.A. Van der Kamp, Dec. 27, 1816
"What havoc has been made of books through every century of the Christian era? Where are fifty gospels, condemned as spurious by the bull of Pope Gelasius? Where are the forty wagon-loads of Hebrew manuscripts burned in France, by order of another pope, because suspected of heresy? Remember the 'index expurgatorius', the inquisition, the stake, the axe, the halter and the guillotine."
..........To John Taylor
"The priesthood have, in all ancient nations, nearly monopolized learning. And ever since the Reformation, when or where has existed a Protestant or dissenting sect who would tolerate A FREE INQUIRY? The blackest billingsgate, the most ungentlemanly insolence, the most yahooish brutality, is patiently endured, countenanced, propagated, and applauded. But touch a solemn truth in collision with a dogma of a sect, though capable of the clearest proof, and you will find you have disturbed a nest, and the hornets will swarm about your eyes and hand, and fly into your face and eyes."
..........To John Taylor
“I am tempted to think that this would be the best of all possible worlds if there was no religion in it.”
"The Christian god is a three headed monster, cruel, vengeful, and capricious. If one wishes to know more of this raging, three headed beast-like god, one only needs to look at the caliber of people who say they serve him. They are always of two classes: fools and hypocrites."
"I do not find in orthodox Christianity one redeeming feature."
"Christianity...(has become) the most perverted system that ever shone on man. ...Rogueries, absurdities and untruths were perpetrated upon the teachings of Jesus by a large band of dupes and importers led by Paul, the first great corrupter of the teaching of Jesus."
When we see religion split into so many thousands of sects, and I may say Christianity itself divided into it's thousands also, who are disputing, anathematizing, and where the laws permit, burning and torturing one another for abstractions which no one of them understand, and which are indeed beyond the comprehension of the human mind, into which of the chambers of this Bedlam would a man wish to thrust himself. The sum of all religion as expressed by it's best preacher, "fear god and love thy neighbor,' contains
no mystery, needs no explanation - but this wont do. It gives no scope to make dupes; priests could not live by it."
..........Letter to George Logan, November 12, 1816
"In every country and every age, the priest has been hostile to liberty. He is always in alliance with the despot ... they have perverted the purest religion ever preached to man into mystery and jargon, unintelligible to all mankind, and therefore the safer engine for their purpose."
..........To Horatio Spafford, March 17, 1814
"Is uniformity attainable? Millions of innocent men, women and children, since the introduction of Christianity, have been burnt, tortured, fined, imprisoned; yet we have not advanced an inch towards uniformity. What has been the effect of coercion? To make one half the world fools, and the other half hypocrites. To support roguery and error all over the earth."
.........."Notes on Virginia"
"Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason than that of blindfolded fear."
..........To Peter Carr, Aug. 10, 1787
"But a short time elapsed after the death of the great reformer of the Jewish religion, before his principles were departed from by those who professed to be his special servants, and perverted into an engine for enslaving mankind, and aggrandizing their oppressors in Church and State."
..........To S. Kercheval, 1810
"On the dogmas of religion, as distinguished from moral principles, all mankind, from the beginning of the world to this day, have been quarreling, fighting, burning and torturing one another, for abstractions unintelligible to themselves and to all others, and absolutely beyond the comprehension of the human mind."
..........To Carey, 1816
"That Jesus did not mean to impose himself on mankind as the son of God, physically speaking, I have been convinced by the writings of men more learned than myself in that lore."
..........To Story, Aug. 4, 1820
"The doctrines of Jesus are simple, and tend all to the happiness of man. But compare with these the demoralizing dogmas of Calvin.
1. That there are three Gods.
2. That good works, or the love of our neighbor, is nothing.
3. That faith is every thing, and the more incomprehensible the proposition, the more merit the faith.
4. That reason in religion is of unlawful use.
5. That God, from the beginning, elected certain individuals to be saved, and certain others to be damned; and that no crimes of the former can damn them; no virtues of the latter save."
..........To Benjamin Waterhouse, Jun. 26, 1822
"The truth is, that the greatest enemies of the doctrine of Jesus are those, calling themselves the expositors of them, who have perverted them to the structure of a system of fancy absolutely incomprehensible, and without any foundation in his genuine words. And the day will come, when the mystical generation of Jesus, by the Supreme Being as his father, in the womb of a virgin, will be classed with the fable of the generation of Minerva in the brain of Jupiter."
..........To John Adams, Apr. 11, 1823
"I do not believe in the creed professed by the Jewish church, by the Roman church, by the Greek church, by the Turkish church, by the Protestant church, nor by any church that I know of. My own mind is my own church."
"All national institutions of churches, whether Jewish, Christian, or Turkish, appear to me no other than human inventions, set up to terrify and enslave mankind, and monopolize power and profit."
"I would not dare to so dishonor my Creator God by attaching His name to that book (the Bible)."
"It is the duty of every true Deist to vindicate the moral justice of God against the evils of the Bible."
"Among the most detestable villains in history, you could not find one worse than Moses. Here is an order, attributed to 'God' to butcher the boys, to massacre the mothers and to debauch and rape the daughters. I would not dare so dishonor my Creator's name by (attaching) it to this filthy book (the Bible)."
"Accustom a people to believe that priests and clergy can forgive sins...and you will have sins in abundance."
"The nearest I can make it out, 'Love your enemies' means, 'Hate your Friends'."
The way to see by faith is to shut the eye of reason.
-- Poor Richard's Almanack, 1758
"If we look back into history for the character of the present sects in Christianity, we shall find few that have not in their turns been persecutors, and complainers of persecution. The primitive Christians thought persecution extremely wrong in the Pagans, but practiced it on one another. The first Protestants of the Church of England blamed persecution in the Romish Church, but practiced it upon the Puritans. They found it wrong in Bishops, but fell into the practice themselves both here (England) and in New England."
"As to Jesus of Nazareth...I think the system of morals and his religion, as he left them to us, the best the world ever saw or is likely to see; but I apprehend it has received various corrupting changes, and I have, with most of the present dissenters in England, some doubts as to his divinity."
"I cannot conceive otherwise than that He, the Infinite Father, expects or requires no worship or praise from us, but that He is even infinitely above it."
.........."Articles of Belief and Acts of Religion", Nov. 20, 1728
"Religion and government will both exist in greater purity, the less they are mixed together."
"What influence, in fact, have ecclesiastical establishments had on society? In some instances they have been seen to erect a spiritual tyranny on the ruins of the civil authority; on many instances they have been seen upholding the thrones of political tyranny; in no instance have they been the guardians of the liberties of the people. Rulers who wish to subvert the public liberty may have found an established clergy convenient auxiliaries. A just government, instituted to secure and perpetuate it, needs them not."
.........."A Memorial and Remonstrance", 1785
"Experience witnesseth that ecclesiastical establishments, instead of maintaining the purity and efficacy of religion, have had a contrary operation. During almost fifteen centuries has the legal establishment of Christianity been on trial. What has been its fruits? More or less, in all places, pride and indolence in the clergy; ignorance and servility in the laity; in both, superstition, bigotry and persecution."
..........."A Memorial and Remonstrance", 1785
"The bible is not my book and Christianity is not my religion. I could never give assent to the long complicated statements of Christian dogma."
"My earlier views of the unsoundness of the Christian scheme of salvation and the human origin of the scriptures, have become clearer and stronger with advancing years and I see no reason for thinking I shall ever change them."