"I have sworn eternal hostility against every form of tyranny over the mind of man."
This is the famous quote from the Jefferson memorial. The full quote, from Jeffersons letter to Dr. Benjamin Rush - Monticello, Sep. 23, 1800 reads:

"I promised you a letter on Christianity, which I have not forgotten. On the contrary, it is because I have reflected on it, that I find much more time necessary for it than I can at present dispose of. I have a view of the subject which ought to displease neither the rational Christian nor Deists, and would reconcile many to a character they have too hastily rejected. I do not know that it would reconcile the genus irritabile vatum who are all in arms against me. Their hostility is on too interesting ground to be softened. The delusion into which the X. Y. Z. plot shewed it possible to push the people; the successful experiment made under the prevalence of that delusion on the clause of the constitution, which, while it secured the freedom of the press, covered also the freedom of religion, had given to the clergy a very favorite hope of obtaining an establishment of a particular form of Christianity thro' the U. S.; and as every sect believes its own form the true one, every one perhaps hoped for his own, but especially the Episcopalians & Congregationalists. The returning good sense of our country threatens abortion to their hopes, & they 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: & enough too in their opinion, & this is the cause of their printing lying pamphlets against me, forging conversations for me with Mazzei, Bishop Madison, &c., which are absolute falsehoods without a circumstance of truth to rest on; falsehoods, too, of which I acquit Mazzei & Bishop Madison, for they are men of truth.