One of the main driving forces of the Emancipation declaration was the need to liberate the slaves.
Explanation:
While the liberation of slaves had started, the numbers aren't that many and most of the slaves were still bonded and kept in captivity. But with the Proclamation came the rectification of making it mandatory to liberate all the slaves. This proclamation was made by Abraham Lincoln in the hope that the war will end and hoped the slaves will revolt against their masters. But this proclamation was effective only in the territories that are in rebellion and not to areas that are already under the Union or the Border States.
