“An injured friend is the bitterest of foes.”

“Whenever any form of government becomes destructive of these ends [life, liberty, and the pursuit of happiness] it is the right of the people to alter or abolish it, and to institute new government...” 

“A coward is much more exposed to quarrels than a man of spirit.”

“Some are whigs, liberals, democrats, call them what you please. Others are tories, serviles, aristocrats, &c. The latter fear the people, and wish to transfer all power to the higher classes of society; the former consider the people as the safest depository of power in the last resort; they cherish them therefore, and wish to leave in them all the powers to the exercise of which they are competent.”

“Of all machines, the human heart is the most complicated and inexplicable.”

“I'm a greater believer in luck, and I find the harder I work the more I have of it”

“I hope that we shall crush in its birth the aristocracy of our monied corporations which dare already to challenge our government to a trial of strength, and bid defiance to the laws of our country.”

“The object of walking is to relax the mind. You should therefore not permit yourself even to think while you walk. But divert your attention by the objects surrounding you.”

“And to preserve their independence, we must not let our rulers load us with perpetual debt. We must make our election between economy and liberty, or profusion and servitude. If we run into such debts, as that we must be taxed in our meat and in our drink, in our necessaries and our comforts, in our labors and our amusements, for our callings and our creeds, as the people of England are, our people, like them, must come to labor sixteen hours in the twenty-four, give the earnings of fifteen of these to the government for their debts and daily expenses; and the sixteenth being insufficient to afford us bread, we must live, as they now do, on oatmeal and potatoes; have no time to think, no means of calling the mismanagers to account; but be glad to obtain subsistence by hiring ourselves to rivet their chains on the necks of our fellow-sufferers.” 

“The most valuable of all talents is that of never using two words when one will do.”

“May it [American independence] be to the world, what I believe it will be, (to some parts sooner, to others later, but finally to all,) the signal of arousing men to burst the chains under which monkish ignorance and superstition had persuaded them to bind themselves, and to assume the blessings and security of self-government. That form which we have substituted, restores the free right to the unbounded exercise of reason and freedom of opinion. All eyes are opened, or opening, to the rights of man. The general spread of the light of science has already laid open to every view the palpable truth, that the mass of mankind has not been born with saddles on their backs, nor a favored few booted and spurred, ready to ride them legitimately... These are grounds of hope for others. For ourselves, let the annual return of this day forever refresh our recollections of these rights, and an undiminished devotion to them.

“The attempt of Lavoisier to reform chemical nomenclature is premature. One single experiment may destroy the whole filiation of his terms; and his string of sulphates, sulphites, and sulphures, may have served no end than to have retarded the progress of science by a jargon, from the confusion of which time will be requisite to extricate us.” 

“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.

“To your request of my opinion of the manner in which a newspaper should be conducted, so as to be most useful, I should answer, ‘by restraining it to true facts & sound principles only.’ Yet I fear such a paper would find few subscribers. It is a melancholy truth, that a suppression of the press could not more compleatly deprive the nation of its benefits, than is done by its abandoned prostitution to falsehood. Nothing can now be believed which is seen in a newspaper. Truth itself becomes suspicious by being put into that polluted vehicle. The real extent of this state of misinformation is known only to those who are in situations to confront facts within their knolege with the lies of the day. I really look with commiseration over the great body of my fellow citizens, who, reading newspapers, live & die in the belief, that they have known something of what has been passing in the world in their time; whereas the accounts they have read in newspapers are just as true a history of any other period of the world as of the present, except that the real names of the day are affixed to their fables. General facts may indeed be collected from them, such as that Europe is now at war, that Bonaparte has been a successful warrior, that he has subjected a great portion of Europe to his will, &c., &c.; but no details can be relied on. I will add, that the man who never looks into a newspaper is better informed than he who reads them; inasmuch as he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. He who reads nothing will still learn the great facts, and the details are all false.” —Letter to John Norvell, 14 June 1807 [Works 10:417--18]” 

“Dependence begets subservience and venality, suffocates the germ of virtue, and prepares fit tools for the designs of ambition.”