"The purpose of separation of church and state is to keep forever from these shores the ceaseless strife that has soaked the soil of Europe in blood for centuries."
-James Madison
"During almost fifteen centuries has the legal establishment of Christianity been on trial. What have 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...What influence in fact have ecclesiastical establishments had on Civil Society? In some instances they have been seen to erect a spiritual tyranny on the ruins of the Civil authority; in many instances they have been seen upholding the thrones of political tyranny: in no instance have they been seen the guardians of the liberties of the people. Rulers who wished to subvert the public liberty, may have found an established Clergy convenient auxiliaries. A just Government instituted to secure & perpetuate it needs them not."
-James Madison
"It was the Universal opinion of the Century preceding the last, that Civil Government could not stand without the prop of a religious establishment; and that the Christian religion itself, would perish if not supported by the legal provision for its clergy. The experience of Virginia conspicuously corroborates the disproof of both opinions. The Civil Government, tho' bereft of everything like an associated hierarchy, possesses the requisite stability and performs its functions with complete success; whilst the number, the industry, and the morality of the priesthood, and the devotion of the people have been manifestly increased by the TOTAL SEPARATION OF THE CHURCH FROM THE STATE."
-James Madison
"Constitution of the United States the danger of encroachment by Ecclesiastical Bodies, may be illustrated by precedents already furnished in their short history."
[attempts where religious bodies had already tried to encroach on the government]. [James Madison, Detached Memoranda, 1820]
"History, I believe, furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance of which their civil as well as religious leaders will always avail themselves for their own purposes."
-Thomas Jefferson to Alexander von Humboldt, Dec. 6, 1813.
"They [the clergy] believe that any portion of power confided to me, will be exerted in opposition to their schemes. And they believe rightly; for I have sworn upon the altar of god, eternal hostility against every form of tyranny over the mind of man. But this is all they have to fear from me: and enough, too, in their opinion."
-Thomas Jefferson to Dr. Benjamin Rush, Sept. 23, 1800
"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? "
-John Adams
"All national institutions of churches, whether Jewish, Christian, or Turkish (Muslim), appear to me no other than human inventions, set up to terrify and enslave mankind, and monopolize power and profit. "
-Thomas Paine, [The Age of Reason]