“The object most interesting to me for the residue of my life, will be to see you both developing daily those principles of virtue and goodness which will make you valuable to others and happy in yourselves, and acquiring those talents and that degree of science which will guard you at all times against ennui, the most dangerous poison of life. A mind always employed is always happy. This is the true secret, the grand recipe for felicity....In a world which furnishes so many employments which are useful, and so many which are amusing, it is our own fault if we ever know what ennui is...”

“No body wishes more than I do to see such proofs as you exhibit, that nature has given to our black brethren, talents equal to those of the other colors of men, and that the appearance of a want of them is owing merely to the degraded condition of their existence, both in Africa & America.”

“It is incumbent on every generation to pay its own debts as it goes. A principle which if acted on would save one-half the wars of the world.”

“If we could believe that he [Jesus] really countenanced the follies, the falsehoods, and the charlatanism which his biographers [Gospels] father on him, and admit the misconstructions, interpolations, and theorizations of the fathers of the early, and the fanatics of the latter ages, the conclusion would be irresistible by every sound mind that he was an impostor... We find in the writings of his biographers matter of two distinct descriptions. First, a groundwork of vulgar ignorance, of things impossible, of superstitions, fanaticisms and fabrications... That sect [Jews] had presented for the object of their worship, a being of terrific character, cruel, vindictive, capricious and unjust... Jesus had to walk on the perilous confines of reason and religion: and a step to right or left might place him within the gripe of the priests of the superstition, a blood thirsty race, as cruel and remorseless as the being whom they represented as the family God of Abraham, of Isaac and of Jacob, and the local God of Israel. They were constantly laying snares, too, to entangle him in the web of the law... 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.

“There exists indeed an opposition to it [building of UVA, Jefferson's secular college] by the friends of William and Mary, which is not strong. The most restive is that of the priests of the different religious sects, who dread the advance of science as witches do the approach of day-light; and scowl on it the fatal harbinger announcing the subversion of the duperies on which they live. In this the Presbyterian clergy take the lead. The tocsin is sounded in all their pulpits, and the first alarm denounced is against the particular creed of Doctr. Cooper; and as impudently denounced as if they really knew what it is.

“The only security of all is in a free press.”

“The policy of the American government is to leave its citizens free, neither restraining them nor aiding them in their pursuits.”

“When the subject is strong, simplicity is the only way to treat it.” 

“New York, like London, seems to be a cloacina [toilet] of all the depravities of human nature.”

“...never [enter] into dispute or argument with another. I never saw an instance of one of two disputants convincing the other by argument. I have seen many, on their getting warm, becoming rude, & shooting one another. ... When I hear another express an opinion which is not mine, I say to myself, he has a right to his opinion, as I to mine; why should I question it? His error does me no injury, and shall I become a Don Quixote, to bring all men by force of argument to one opinion? ... There are two classes of disputants most frequently to be met with among us. The first is of young students, just entered the threshold of science, with a first view of its outlines, not yet filled up with the details & modifications which a further progress would bring to their knoledge. The other consists of the ill-tempered & rude men in society, who have taken up a passion for politics. ... Consider yourself, when with them, as among the patients of Bedlam, needing medical more than moral counsel. Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics. In the fevered state of our country, no good can ever result from any attempt to set one of these fiery zealots to rights, either in fact or principle. They are determined as to the facts they will believe, and the opinions on which they will act. Get by them, therefore, as you would by an angry bull; it is not for a man of sense to dispute the road with such an animal.”

“He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation.”

“But every difference of opinion is not a difference of principle.”

“Nobody is better than you and remember, you are better than nobody.

“War is an instrument entirely inefficient toward redressing wrong; and multiplies, instead of indemnifying losses.”

“...as we advance in life these things fall off one by one , and I suspect we are left with only Homer and Virgil, perhaps with only Homer alone.”