Brief Summary
The Setup
In the wake of tremendous losses by both the North and the South in the Civil War, Lincoln was asked to speak at the dedication ceremony for the national cemetery at Gettysburg. His speech paid respects to the fallen soldiers while reinforcing that a failure to take back the South would be a failure to maintain the principles set out by America's Founding Fathers.
Oh, yeah, and did we mention that Abe had smallpox while delivering this speech? What a boss.
The Text
Right at the top of the speech, President Lincoln basically said, "Hey guys, remember that the revolution wasn't all that long ago, and right now we're in almost as desperate a circumstance."
People at the time were shocked by the scale of the conflict, and by the casualty counts printed in the papers. Spirits were understandably down.
But Abe went on to say that it was essential to tune out the haters that wanted to sue for peace with the Confederates because they were fighting for the very survival of the United States. As Lincoln had said years before, "A house divided against itself cannot stand."
He saw the impossibility of two separate societies coexisting in America. Eventually, either slavery or abolitionism would have to win out. Clear eyes, full hearts, can't lose.
TL;DR
Like Henry V or Gordon Bombay, President Abraham Lincoln delivered one heck of a halftime speech that spurred on the Union to a victory two years later.