“Some men look at constitutions with sanctimonious reverence, and deem them like the ark of the covenant, too sacred to be touched. They ascribe to the men of the preceding age a wisdom more than human, and suppose what they did to be beyond amendment...But I know also, that laws and institutions must go hand in hand with the progress of the human mind. As that becomes more developed, more enlightened, as new discoveries are made, new truths disclosed, and manners and opinions change with the change of circumstances, institutions must advance also, and keep pace with the times.”

“Good humor is one of the preservatives of our peace and tranquility” 

“Never spend your money before you have earned it.”

“As Thomas Jefferson proclaimed, “In matters of fashion, swim with the current. In matters of conscience, stand like a rock.”

“If the present Congress errs in too much talking, how can it be otherwise in a body to which the people send 150 lawyers, whose trade it is to question everything, yield nothing, & talk by the hour? That 150 lawyers should do business together ought not to be expected.”

“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]” 

“no people can be both ignorant and free.”

“All tyranny needs to gain a foothold is for people of good conscience to remain silent.”

“I set out on this ground, which I suppose to be self-evident, that the earth belongs in usufruct to the living.”

“...it is not to be understood that I am with him [Jesus] in all his doctrines. I am a Materialist, he takes the side of spiritualism; he preaches the efficacy of repentance toward forgiveness of sin. I require a counterpoise of good works to redeem it... Among the sayings & discourses imputed to him by his biographers, I find many passages of fine imagination, correct morality, and of the most lovely benevolence: and others again of so much ignorance, so much absurdity, so much untruth, charlatanism, and imposture, as to pronounce it impossible that such contradictions should have proceeded from the same being.

“I find friendship to be like wine, raw when new, ripened with age, the true old man's milk and restorative cordial.”

“A nation which expects to be ignorant and free, in a state of civilization, expects that which never was and never will be.”

“All is safe where all can read," is a quotation from Thomas Jefferson showing his belief in the importance of everyone knowing how to and being able/allowed to read. I would like to take it one step further.  I would say, "All is BETTER when all can read." No matter what you like to read, the ability to read it, understand it, and enjoy it, truly enriches your life.”

“I cannot live without books: but fewer will suffice where amusement, and not use, is the only future object.” 

“They (religions) dread the advance of science as witches do the approach of daylight and scowl on the fatal harbinger announcing the subversions of the duperies on which they live.”