The rock-bottom foundation of Abraham Lincoln's religious faith was the ultra-Calvinism of his boyhood. He was reared a Predestinarian Baptist; and while he never became a Baptist he never ceased to be a Predestinarian. To this he added a strong rationalistic tendency, inherent in his nature, and strengthened by his study of Paine and Volney. This also he never wholly outgrew. As a lawyer who was not well read, pleading before juries that cared little for the letter of the law, he was accustomed to reduce his cases to simple principles of elementary justice, and to rest all upon these principles. This habit of thought and practice he applied also to his theology. His early recollection of the epitaph of Johnny Kongapod was nothing less than the application of the Golden Rule to theology--the assurance of an eternal justice throned in heaven and intelligible on earth.
Thus, when he argued in favor of universal salvation he did it upon the basis of the old Calvinistic theology with which he had been familiar all his life. If God was, indeed, absolute sovereign, and as good as He was great, and willed not that any should perish, then no one could finally perish. Universal salvation became logically and ethically compulsory. The Christ who tasted death for every man, did so as the necessary means to the efficiency of a plan of salvation whereby the curse of the fall was fully offset by the sacrifice of Christ, at the instance of the sovereign will of God. As in Adam all died, even so in Christ were all made alive. His theory of universal salvation was the logical expression of his determinism, influenced by his rationalism and confirmed by his appeal to a justice that would not accept a fall more universal than the atonement of Christ. This was not because Lincoln approached the theme from the direction of the grace of Christ, but of the irresistibility of a divine decree. He profoundly believed himself an instrument of the divine will, believing that will to be right, and creation's final law.
If it were asked, where in such a system as his he found a place for the forgiveness of sins, the answer would be first that he had no system, and secondly that he found no place for the doctrine; but it would then be necessary to add that he found the doctrine, nevertheless. He had no system. He thought without logical method. But his thinking was in right lines. He followed simple paths, "blazed" through technicalities and in quite thorough disregard of them. As his office desk was in confusion, and he kept a package marked, "When you don't find it anywhere else, look here," so he had in his thinking a parcel of unassorted first principles to which he recurred when he needed them. Forgiveness and law were to him two unreconciled postulates; but law he had to assume, even though he denied forgiveness. But if he did not admit belief in forgiveness, he did believe in mercy, for he himself was merciful, and he believed that he would be merciful to God if he were God and God were man. Stanton could argue him down as to the necessity for shooting a soldier who slept on duty, but Lincoln injected an intuitive, and from Stanton's point of view, an unreasonable and a certainly unarticulated, element of mercy that forbade the killing of this particular boy.