Before the Battle of Antietam, President Abraham Lincol sent a telegram to General George B. McClellan, commanding the Union Army of the Potomac:
GOD BLESS YOU AND ALL WITH YOU
DESTROY THE REBEL ARMY IF POSSIBLE
McClellan, with an army nearly twice the size of Lee's, thought that he was outnumbered:
"One battle lost, and almost all would have been lost. Lee's army might then have marched as it pleased on Washington, Baltimore, Philadelphia, or New York."
Lee knew that he was outnumbered, but he had brought this Army of Northern Virginia north of the Potomac River to win a great victory:
"We will make our stand."
The evening before the battle, combat artist Edwin Forbes sketched the soldiers of the Union First Corps as they waded across Antietam Creek. The crossing was well to the north of Sharpsburg, so the Southerners knew that the first attack would fall on Major General "Stonewall" Jackson's Corps waiting at the Dunker Church.
Major General Joseph Hooker commanded the First Corps, and he was ready:
"If they had let us start earlier, we might have finished tonight."