“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...”

“If there is one principle more deeply rooted in the mind of every American, it is that we should have nothing to do with conquest.”

“I am certainly not an advocate for frequent and untried changes in laws and constitutions...but I know also that laws and constitutions must go hand in hand with the progress of the human mind.....”

“If our house be on fire, without inquiring whether it was fired from within or without, we must try to extinguish it.”

“I find that the harder I work, the more luck I seem to have.”

“The laws that forbid the carrying of arms... disarm only those who are neither inclined nor determined to commit crimes.”

“Leave no authority existing not responsible to the people.”

“Health, learning and virtue will ensure your happiness; they will give you a quiet conscience, private esteem and public honour.”

“There is not a sprig of grass that shoots uninteresting to me.”

“I never will, by any word or act, bow to the shrine of intolerance or admit a right of inquiry into the religious opinions of others.”

“I believe that banking institutions are more dangerous to our liberties than standing armies.” 

“Our greatest happiness does not depend on the condition of life in which chance has placed us, but is always the result of a good conscience, good health, occupation, and freedom in all just pursuits.”

“...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.”

“Was the government to prescribe us our medicine and diet, our bodies would be in such keeping as our souls are now."

“Difference of opinion is advantageous in religion. The several sects perform the office of a Censor morum over each other. 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 one 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. Let us reflect that it is inhabited by a thousand millions of people. That these profess probably a thousand different systems of religion. That ours is but one of that thousand. That if there be but one right, and ours that one, we should wish to see the 999 wandering sects gathered into the fold of truth. But against such a majority we cannot effect this by force. Reason and persuasion are the only practicable instruments. To make way for these, free enquiry must be indulged; and how can we wish others to indulge it while we refuse it ourselves.”