When the Union army came cautiously into Fredericksburg, a Union man put the orders in the hands of McClellan. Lee's brilliant plan of campaign was in the hands of his adversary. The bugles sounded in the blue ranks and at the double quick the Union army marched for the passes of South Mountain to overtake Lee. They drove his army through the passes before he could call back his other divisions, and on September 17, the bloodiest day of the Civil War, defeated it at the fords of the Antietam.
When the baffled army of Lee had crossed the Potomac back into Virginia, Lincoln told his advisers how he had covenanted with God that, if the North was victorious in the struggle in Maryland, he would show his gratitude by freeing the slaves. A careless staff officer wrapped Lee's order about his tobacco, and the plan of the campaign was in the hands of the adversary. Surprise was impossible; defeat certain. The North was freed from invasion, and the Proclamation of Emancipation was issued. All of this was due to one of those strange events which, so insignificant in itself, yet under Him--"Who sees with equal eye as God of all, a hero perish or a sparrow fall"--is fateful to decide the issue of nations. --McCartney
(See Also: Hand On The Helm)