It implies that Lincoln recognized he had no fiat powers over slavery in the states that weren't in rebellion. You guys always attack Lincoln for being a dictator, then attack him for not using his dictatorial powers. For the record, three of the five loyal slave states--West Virginia, Missouri, and Maryland--ended it on their own before war's end. Furthermore, Lincoln fully supported passage of the 13th amendment, even insisting on it being included in the 1864 Republican platform. It had already passed the Senate in April, 1864 but Democrats in the House blocked it until after the November election. Once passed, Lincoln promptly signed it and it went to the states.
Mississippi, by the way, didn't ratify the 13th until 1995.
It sure does. Respect for the Constitution for one. Lincoln could not end slavery anywhere, and could not free the slaves in those areas not in rebellion because the Constitution prevented it. It took the 13th Amendment to end slavery once and for all.