“Few men have virtue to withstand the highest bidder.”
Letter to Major-General Robert Howe (17 August 1779), published in "The Writings of George Washington": 1778-1779, edited by Worthington Chauncey Ford (1890)
Paraphrased variants:
Few men have the virtue to withstand the highest bidder.
Few men have virtue enough to withstand the highest bidder
1770s
Help us to complete the source, original and additional information
George Washington 186
first President of the United States 1732–1799Related quotes

On Nick Clegg's social mobility pledges, during a debate in the House of Commons http://www.telegraph.co.uk/news/politics/8441262/Harriet-Harman-facing-questions-over-sons-internship.html, 11 April 2011.

Source: An Ordinary Person's Guide to Empire (2005), p. 48

Election speech, Canterbury, Victoria, 29 October, 1958 https://electionspeeches.moadoph.gov.au/speeches/1958-robert-menzies
Second Term as Prime Minister (1949-1966)

“People who have no vices, have very few virtues.”
According to The Inner Life of Abraham Lincoln (1867) by F. B. Carpenter, Lincoln quoted this as having been said to him by a fellow-passenger in a stagecoach. See also "Washington during the War", Macmillan's Magazine 6:24 http://books.google.com/books?id=rB4AAAAAYAAJ&pg=PA24&dq=folks (May 1862)
Posthumous attributions
Variant: It's my experience that folks who have no vices have generally very few virtues.

“The highest proof of virtue is to possess boundless power without abusing it.”
Review of Aiken’s Life of Addison (1843)

“Fortune blinds men when she does not wish them to withstand the violence of her onslaughts.”
Book V, sec. 37
History of Rome

Speech at Arlington Cemetery, Decoration Day (30 May 1868)
1860s
Context: I am oppressed with a sense of the impropriety of uttering words on this occasion. If silence is ever golden, it must be here, beside the graves of fifteen thousand men, whose lives were more significant than speech, and whose death was a poem, the music of which can never be sung. With words we make promises, plight faith, praise virtue. Promises may not be kept, plighted faith may be broken, and vaunted virtue be only the cunning mask of vice. We do not know one promise these men made, one pledge they gave, one word they spoke: but we do know they summed up and perfected, by one supreme act, the highest virtues of men and citizens. For love of country they accepted death, and thus resolved all doubts, and made immortal their patriotism and their virtue.

Observations on the Drawing Up of Laws (1774)
Context: In any country where talent and virtue produce no advancement, money will be the national god. Its inhabitants will either have to possess money or make others believe that they do. Wealth will be the highest virtue, poverty the greatest vice. Those who have money will display it in every imaginable way. If their ostentation does not exceed their fortune, all will be well. But if their ostentation does exceed their fortune they will ruin themselves. In such a country, the greatest fortunes will vanish in the twinkling of an eye. Those who don't have money will ruin themselves with vain efforts to conceal their poverty. That is one kind of affluence: the outward sign of wealth for a small number, the mask of poverty for the majority, and a source of corruption for all.