“Drinking makes such fools of people, and people are such fools to begin with, that it's compounding a felony.”

Variant: It's easier to fool people than to convince them that they have been fooled.

Source: The Bridge

This is probably the most famous of apparently apocryphal remarks attributed to Lincoln. Despite it being cited variously as from an 1856 speech, or a September 1858 speech in Clinton, Illinois, there are no known contemporary records or accounts substantiating that he ever made the statement. The earliest known appearance is October 29, 1886 in the Milwaukee Daily Journal http://anotherhistoryblog.blogspot.com/2009/02/fooling-people-earlier.html. It later appeared in the New York Times on August 26 http://query.nytimes.com/gst/abstract.html?res=F30817FF3E5413738DDDAF0A94D0405B8784F0D3 and August 27 http://query.nytimes.com/gst/abstract.html?res=F00E15FF3E5413738DDDAE0A94D0405B8784F0D3, 1887. The saying was repeated several times in newspaper editorials later in 1887. In 1888 and, especially, 1889, the saying became commonplace, used in speeches, advertisements, and on portraits of Lincoln. In 1905 and later, there were attempts to find contemporaries of Lincoln who could recall Lincoln saying this. Historians have not, generally, found these accounts convincing. For more information see two articles in For the People: A Newsletter of the Abraham Lincoln Association, "'You Can Fool All of the People' Lincoln Never Said That", by Thomas F. Schwartz ( V. 5, #4, Winter 2003, p. 1 http://abrahamlincolnassociation.org/Newsletters/5-4.pdf) and "A New Look at 'You Can Fool All of the People'" by David B. Parker ( V. 7, #3, Autumn 2005, p. 1 http://abrahamlincolnassociation.org/Newsletters/7-3.pdf); also the talk page. The statement has also sometimes been attributed to P. T. Barnum, although no references to this have been found from the nineteenth century.
Variants:
You can fool all the people some of the time, and some of the people all of the time, but you cannot fool all of the people all of the time.
You can fool all of the people some of the time, and some of the people all of the time, but you can't fool all of the people all of the time.
You can fool all the people some time, you can fool some of the people all of the time, but you can not fool all the people all the time.
Disputed

Attributed

Source: The Rise of the Hotel Dumort

As quoted in One Big Fib : The Incredible Story of the Fraudulent First International Bank of Grenada (2003) by Owen Platt, p. 37