What were president Lincoln's reasons for issuing the emancipation proclamation, and why did it free only those slaves who lived in the confederate states

Well you see he freed the slaves in the north states because the northern states were doing more of the industrial work, while the state in the south were doing farming and stuff like that. The states in the north didn't really need slaves anymore, but the states down south were not willing to let them go because they were making good profit off of free labor the slaves were giving them. So the south states decided that they were going to become a different nation and separate out of the usa all over not wanting to lose slaves.