“It is while we are young that the habit of industry is formed. If not then, it never is afterward.”

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

“You have heard of the new chemical nomenclature endeavored to be introduced by Lavoisier, Fourcroy, &c. Other chemists of this country, of equal note, reject it, and prove in my opinion that it is premature, insufficient and false. These latter are joined by the British chemists; and upon the whole, I think the new nomenclature will be rejected, after doing more harm than good. There are some good publications in it, which must be translated into the ordinary chemical language before they will be useful.”

“I am bold to Say that neither you nor I, will live to See the Course which 'the Wonders of the Times' will take. Many Years, and perhaps Centuries must pass, before the current will acquire a Settled direction... yet Platonic, Pythagoric, Hindoo, and cabalistic Christianity, which is Catholic Christianity, and which has prevailed for 1,500 years, has received a mortal wound, of which the monster must finally die. Yet so strong is his constitution, that he may endure for centuries before he expires.

“The people cannot be all, and always, well informed. The part which is wrong will be discontented, in proportion to the importance of the facts they misconceive. If they remain quiet under such misconceptions, it is lethargy, the forerunner of death to the public liberty. ... What country before ever existed a century and half without a rebellion? And what country can preserve its liberties if their rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms. The remedy is to set them right as to facts, pardon and pacify them. What signify a few lives lost in a century or two? The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants. It is its natural manure.”

“There exists indeed an opposition to it [building of UVA, Jefferson's secular college] by the friends of William and Mary, which is not strong. The most restive is that of the priests of the different religious sects, who dread the advance of science as witches do the approach of day-light; and scowl on it the fatal harbinger announcing the subversion of the duperies on which they live. In this the Presbyterian clergy take the lead. The tocsin is sounded in all their pulpits, and the first alarm denounced is against the particular creed of Doctr. Cooper; and as impudently denounced as if they really knew what it is.

“The equal rights of man, and the happiness of every individual, are now acknowledged to be the only legitimate objects of government.”

“Never spend your money before you have it.”

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

“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.” 

“In every country and in every age, the priest has been hostile to liberty. He is always in alliance with the despot, abetting his abuses in return for protection to his own.”

“...We are all Federalists,and we are all Republicans.”

“Nature intended me for the tranquil pursuits of science, by rendering them my supreme delight. But the enormities of the times in which I have lived, have forced me to take a part in resisting them, and to commit myself on the boisterous ocean of political passions.”

“I have often thought that if heaven had given me choice of my position and calling, it should have been on a rich spot of earth, well watered, and near a good market for the productions of the garden. No occupation is so delightful to me as the culture of the earth, and no lucture comparable to that of the garden. Sucha a variety of subjeccts, some one always coming to perfection, the failure of one thing repaired by the succes of another, and instead of one harvest a continued one through the year. Under a total want of demand except for our family table, I am still devoted to the garden.”

“Too old to plant trees for my own gratification, I shall do it for my posterity.”