Both read the same Bible and pray to the same God, and each invokes His aid against the other. It may seem strange that any men should dare to ask a just God's assistance in wringing their bread from the sweat of other men's faces, but let us judge not, that we be not judged. The prayers of both could not be answered. That of neither has been answered fully. The Almighty has His own purposes.
So, if slavery were wrong, by some non-theistic natural law and morals, or whatever, Winthrop's city on a hill wasn't one so much.
He now wills to remove, and that He gives to both North and South this terrible war as the woe due to those by whom the offense came, shall we discern therein any departure from those divine attributes which the believers in a living God always ascribe to Him? Fondly do we hope, fervently do we pray, that this mighty scourge of war may speedily pass away. Yet, if God wills that it continue until all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash shall be paid by another drawn with the sword.
(T)he judgments of the Lord are true and righteous altogether.
Meanwhile, 100 years later, Lyndon Johnson followed up on Lincoln with his "Selma" speech, explicitly calling for full civil rights for African-Americans — and Hispanics.