“As you say of yourself, I too am an Epicurean. I consider the genuine (not the imputed) doctrines of Epicurus as containing everything rational in moral philosophy which Greece and Rome have left us.

“If you want something you've never had You must be willing to do something you've never done.” 

“It is neither wealth nor splendor; but tranquility and occupation which give you happiness.”

“That one generation of men in civil society have no right to make acts to bind another, is a truth that cannot be confused.”

“Indeed I tremble for my country when I reflect that God is Just”

“Do not be too severe upon the errors of the people, but reclaim them by enlightening them.”

“A government big enough to give you everything you want, is strong enough to take everything you have

“...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.”

“[Christianity is] the most ... perverted system that ever shone on man.”

“The most fortunate of us all in our journey through life frequently meet with calamities and misfortunes which greatly afflict us. To fortify our minds against the attacks of these calamities and misfortunes should be one of the principal studies and endeavors of our lives.”

“Our civil rights have no dependence upon our religious opinions more than our opinions in physics or geometry.”

“How much pain they have cost us, the evils which have never happened. --”

“Determine never to be idle. No person will have occasion to complain of the want of time, who never loses any. It is wonderful how much may be done, if we are always doing.”

“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.”

“Perceiving the order of nature to be that individual happiness shall be inseparable from the practice of virtue, I am willing to hope it may have ordained that the fall of the wicked shall be the rise of the good.  To J. Correa de Serra, Monticello, Apr. 19, 1814”