Lincoln was against slavery in his core, but from an economic standpoint he supported slavery and often took legal action as a lawyer to return slaves to their owners. At the same time he also fought to keep slaves from being sent back. it depended on who had the money to pay him.
He had no choice but to preserve the Union which according to most people was the right thing to do, but the slavery thing wasn't done to give anyone civil rights. It was done to break the bank of the confederacy because at that time slaves were a valuable commodity and traded like any other commodity.
The effects are far reaching and well beyond the scope of what I can even begin to write here, but it did change our fundamental beliefs and values as a nation. There is no doubt about that.