Appalled by the casualties and lack of preparation, newspapers and politicians throughout the North called for Grant to be sacked, but Abraham Lincoln declined to do so. Speaking to one Pennsylvania congressman, President Lincoln said "I can't spare this man. He fights!" This is not the most famous thing Lincoln ever said, but it is pretty well known. It is recounted by James McPherson recounts in Battle Cry of Freedom, by biographer Jean Edward Smith in Grant, and by many others.
The only problem is that Lincoln may never have said it. According to William Marvel in Lincoln's Darkest Year: The War in 1862 and Brooks D. Simpson in Ulysses S. Grant: Triumph Over Adversity, 1822-1865, the Pennsylvania politician, Alexander McClure, did not tell anyone about Lincoln's comment until several years after the war. The record shows that Lincoln relied on Grant's superior, General Henry W. Halleck, to determine whether Grant had acted properly at Shiloh, and that Halleck gave Grant a hard time over the next several months.
There are also questions about Confederate General Robert E. Lee's statements on the third day of the Battle of Gettysburg after the Union forces had repulsed Pickett's Charge. According to Shelby Foote in The Civil War: A Narrative, Lee rode among his troops saying "It's all my fault" and "The blame is mine."
To [General Cadmus] Wilcox, who was about as unstrung as [General George]It is considered to be one of Lee's finest moments.
Pickett in reporting that he was not sure that his troops would stand if the
Federals attacked, Lee was particularly solicitous and tender. "Never
mind, General," he told him taking his hand as he spoke. "All
this has been my fault—it is I that have lost this fight, and you must help me
out of it the best way you can."
In this case, the problem is not so much with what Lee said as to who he said it. According to Michael Fellmen in The Making of Robert E Lee, Lee had taken responsibility in order to rally his discouraged brigade commander Wilcox, but
"[t]here is no evidence to corroborate the legend that Lee rode among the commonHe encouraged his foot soldiers, but Fellmen considers the generalized mea culpa unlikely.
soldiers and confessed his failings . . . . It would not have been
in his aristocratic character, nor would it have made good sense in terms of
discipline to have made such a confession to all and sundry, an act that Lee
would have found unacceptably humiliating."
Any Civil War buff worth his salt is probably aware of dozens of cases where the evidence is pretty thin that a famous quote is actually the product of the person to whom it is attributed. Stories about Lincoln and Lee were as likely to be told and retold over the years because they reflected popular understanding of these men as because they accurately reported what really happened.
Evangelical Christians like to tell themselves that unbelievers are unreasonably skeptical about the historicity of the gospels, but no responsible historian takes any written report at face value. They look for corroboration and always recognize the possibility that a story got passed on because it was a good story rather than because it was true. One needs to look no further than the story of the woman caught in adultery to know that this happened in the Bible.