“I was bold in the pursuit of knowledge, never fearing to follow truth and reason to whatever results they led, and bearding every authority which stood in their way. ”

“Never spend your money before you have it.”

“I have no ambition to govern men; it is a painful and thankless office.” 

“Follow truth wherever it may lead you.”

“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.”

“The Constitution of most of our states (and of the United States) assert that all power is inherent in the people; that they may exercise it by themselves; that it is their right and duty to be at all times armed.”

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

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

“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. I knew that age well; I belonged to it, and labored with it. It deserved well of its country. It was very like the present, but without the experience of the present; and forty years of experience in government is worth a century of book-reading; and this they would say themselves, were they to rise from the dead. I am certainly not an advocate for frequent and untried changes in laws and constitutions. I think moderate imperfections had better be borne with; because, when once known, we accommodate ourselves to them, and find practical means of correcting their ill effects. 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. We might as well require a man to wear still the coat which fitted him when a boy, as civilized society to remain ever under the regimen of their barbarous ancestors.” 

“Leave all the afternoon for exercise and recreation, which are as necessary as reading. I will rather say more necessary because health is worth more than learning.”

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

“In matters of principal stand like a rock.”

“On every question of construction (of the Constitution) let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit of the debates, and instead of trying what meaning may be squeezed out of the text, or invented against it, conform to the probable one in which it was passed.”

“The executive power in our government is not the only, perhaps not even the principal, object of my solicitude. The tyranny of the legislature is really the danger most to be feared, and will continue to be so for many years to come. The tyranny of the executive power will come in its turn, but at a more distant period.” 

“The doctor of the future will give no medicine, but will interest his (sic)patient in the care of the human frame, in diet and in the cause and prevention of disease”