Lincoln actually issued the Emancipation Proclamation twice.Abraham Lincoln issued the preliminary Emancipation Proclamation on September 22nd, 1862. It specified that if the Southern states did not cease their rebellion by January 1st, 1863, then Proclamation would go into effect. When the Confederacy did not yield, Lincoln issued the final Emancipation Proclamation on January 1st, 1863
To begin with, the Emancipation Proclamation did not free a single slave. It applied only to slaves in the states "in rebellion" – the Confederacy – where the Union had no power or authority. And it did not apply to the Border States where there still was slavery (Delaware, Maryland, Kentucky, and Missouri). In other words, as Secretary of State William Seward remarked ironically at the time, "We show our sympathy with slavery by emancipating slaves where we cannot reach them and holding them in bondage where we can set them free."
But then, it was not really intended to liberate anybody. It was, as Lincoln took care to spell out, a "military measure," issued under the President’s authority as commander-in-chief, and its real purpose was to undermine the Confederate Army. This would be accomplished, Lincoln hoped, first by encouraging slaves to take over the plantations so that they would no longer be supplying foodstuffs for the soldiers, and second by causing plantation owners serving in the army to desert and rush home to protect their wives and children from the presumably dangerous freedmen.
The Emancipation Proclamation was a firm demonstration of the President’s executive war powers. The Southern states used slaves to support their armies on the field and to manage the home front so more men could go off to fight. In a display of his political genius, President Lincoln shrewdly justified the Emancipation Proclamation as a “fit and necessary war measure” in order to cripple the Confederacy’s use of slaves in the war effort. Lincoln also declared that the Proclamation would be enforced under his power as Commander-in-Chief, and that the freedom of the slaves would be maintained by the “Executive government of the United States.”
The Emancipation Proclamation paved the way for African-Americans to fight for their freedom. Lincoln declared in the Proclamation that African-Americans of “suitable condition, would be received into the armed service of the United States.” Five months after the Proclamation took effect; the War Department of the United States issued General Orders No. 143, establishing the United States Colored Troops (USCT). By the end of the war, over 200,000 African-Americans would serve in the Union army and navy.