“The object most interesting to me for the residue of my life, will be to see you both developing daily those principles of virtue and goodness which will make you valuable to others and happy in yourselves, and acquiring those talents and that degree of science which will guard you at all times against ennui, the most dangerous poison of life. A mind always employed is always happy. This is the true secret, the grand recipe for felicity....In a world which furnishes so many employments which are useful, and so many which are amusing, it is our own fault if we ever know what ennui is...”

“With your talents and industry, with science, and that steadfast honesty, which eternally pursues right, regardless of consequences, you may promise yourself everything but health, without which there is no happiness.”

“Everything is useful which contributes to fix in the principles and practices of virtue.”

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

“Every day is lost in which we do not learn something useful. Man has no nobler or more valuable possession than time.”

“When we see religion split into so many thousand of sects, and I may say Christianity itself divided into its thousands also, who are disputing, anathematizing and where the laws permit burning and torturing one another for abstractions which no one of them understand, and which are indeed beyond the comprehension of the human mind, into which of the chambers of this Bedlam would a man wish to thrust himself.[Letter to George Logan, 12 November 1816]”

“Everything predicted by the enemies of banks, in the beginning, is now coming to pass. We are to be ruined now by the deluge of bank paper. It is cruel that such revolutions in private fortunes should be at the mercy of avaricious adventurers, who, instead of employing their capital, if any they have, in manufactures, commerce, and other useful pursuits, make it an instrument to burden all the interchanges of property with their swindling profits, profits which are the price of no useful industry of theirs.”