Abraham Lincoln (1809-1865) was credited with a line that appeared in many newspapers in 1904:
 
“I am not bound to win, but I am bound to be true. I am not bound to succeed, but I am bound to live up to the light I have. I stand with anybody that stands right, stand with him while he is right, and part with him when he goes wrong.”
 
There is no evidence that Lincoln ever said it. The “I am not bound to win” line was used by U.S. President Barack Obama in 2010.
 
 
14 May 1904, The Reflector (Jeffersonville, IN), pg.. 2, col. 1:
ABRAHAM LINCOLN said: “I am not bound to win, but I am bound to be true. I am not bound to succeed, but I am bound to live up to the light I have. I stand with anybody that stands right, stand with him while he is right, and part with him when he goes wrong.” Do thou even so.
 
26 June 1904, Illinois State Register (Springfield, IL), pg. 18, col. 4:
PERFECT ENGLISH.
A Few Sentences That Were Written by Abraham Lincoln.
(...)
“I am not bound to win, but I am bound to be true. I am not bound to succeed, but I am bound to live up to the light I have. I must stand with anybody that stands right—stand with him, while he is right and part with him when he goes wrong.”
 
Chronicling America
24 September 1904, The Intermountain and Colorado Catholic (Salt Lake City, UT and Denver, CO), pg. 5, col. 2:
LINCOLN’S WORDS.
(...)
“I am not bound to win, but I am bound to be true. I am not bound to succeed, but I am bound to live up to the light I have. I must stand with anybody that stands right, stand with him while he is right, and part with him when he goes wrong.”
 
The White House
March 26, 2010
Remarks by the President to the House Democratic Congress
Capitol Visitor Center Auditorium, Washington, D.C.
(...)
I have the great pleasure of having a really nice library at the White House.  And I was tooling through some of the writings of some previous Presidents and I came upon this quote by Abraham Lincoln:  “I am not bound to win, but I’m bound to be true.  I’m not bound to succeed, but I’m bound to live up to what light I have.”
   
NPR
Honest, Mr. President: Abe Never Said It
by JOHN J. PITNEY JR.
March 25, 201011:43 AM ET
In his remarks to Democratic lawmakers the day before they passed the health care bill, President Obama said: “I was tooling through some of the writings of some previous presidents, and I came upon this quote by Abraham Lincoln: ‘I am not bound to win, but I’m bound to be true. I’m not bound to succeed, but I’m bound to live up to what light I have.’ “
 
The Lincoln quotation was stirring. It was also bogus. There is no documentary evidence that Lincoln ever said any such thing.
(...)
President Reagan used the “bound to be true” line several times. (One may guess that President Obama’s speechwriter got it from a Reagan speech and incorrectly took it for granted that the Gipper’s staff had sourced it.)