Lincoln on Emancipation, the Bible, and God’s Will
Lincoln gave voice to his thinking on the subject in September  when a church delegation from Chicago came to the White House to present a memorial endorsing emancipation… He told the delegates that religious men regularly approached him with advice. They were invariably “certain that they represent the divine will.” But they came with radically opposing views (“the most opposite opinions and advice”), and not all of them could be right. It might even be that all of them were wrong.
And there was the nub of the problem. How could one learn God’s will, and if one could not, how could one make the grave decision…? “If I can learn what it is I will do it!” Lincoln said. But God’s justice was inscrutable. “These are not,” he reminded his memorialists, “the days of miracles.” There would be no “direct revelation.” …Confederate troops were no doubt “expecting God to favor their side” just as Union men thought that God would favor theirs….
But the Chicago Christians replied with a much older idea…Unbeknownst to them, their reply followed the course Lincoln’s own thinking had been taking over the previous weeks. Moral uncertainty, they observed, could not excuse paralysis. “Good men,” they conceded, “differed in their opinions.” But “the truth was somewhere,” and men could not merely set one opinion against another and throw up their hands. The moral leader had to act, had to bring “facts, principles, and arguments” to bear and come to a conclusion as to what justice required
…[W]hen the interview closed, it was clear that Lincoln and his Chicago petitioners were not so far apart after all. “Do not misunderstand me because I have mentioned these objections,” Lincoln told them. “Whatever shall appear to be God’s will I will do.”
34 John Fabian Witt, Lincoln’s Code: The Laws of War in American History (New York: The Free Press/Simon and Schuster, 2013), p. 213.