All this changed in winter of 1862, when Lincoln's adored little son Willie died of typhoid fever in the White House, father weeping uncontrollably in the next room. Mary Lincoln was driven to mysticism by the loss; soon she would be consulting mediums, trying to communicate with Willie on the other side.
Lincoln turned to the Rev. Phineas Gurley of New York Avenue Presbyterian Church, located a few blocks from the White House. Gurley and the president began going on long walks.
During one of the walks, Lincoln converted to Christianity, accepting Jesus as his personal savior. Though he never formally joined any denomination, Lincoln started attending Gurley's church twice a week and studying scripture avidly.
When Joshua Speed, the Springfield store proprietor who was Lincoln's best friend during his carefree days, expressed surprise in 1864 to encounter Abe reading the Bible, Lincoln counseled him somberly, "Take all that you can of this book upon reason and the balance on faith, and you will live and die a happier man."
While this was happening, the course of the Civil War turned horrific. Lincoln was stunned by the bloodshed at Antietam in September 1862, where twice as many men died on a single day as had died in the entire War of 1812. Worse, Antietam was inconclusive, ensuring the carnage would go on.
Lincoln began to adopt the radical religious view that the conflict was not meant to end quickly because the Civil War was God's retribution against the United States for holding slaves. That is, God actually wanted huge numbers of Americans to die, paying for the nation's sins.
Imagine President Bush saying that he believed the divine wanted Americans to die in terrorism attacks as retribution for times when Americans deliberately killed the innocent, such as the bombing of Dresden. Yet Lincoln said as much: "In the present Civil War it is quite possible that God's purpose is something different from the purpose of either party. God wills the contest and wills that it shall not end yet."
In 1863, Lincoln declared a National Fast Day, saying, "We know that, by divine law, nations like individuals are subjected to punishments and chastisement in this world." The war, he went on, was "a punishment inflicted upon us for our presumptuous sins."
Lincoln's increasingly fatalistic view was summed in his second inaugural address, in words that now line the Lincoln Memorial in Washington: that God wills the Civil War to continue "until all the wealth piled by the bond-man's two hundred years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash, shall be paid with another drawn with the sword."
As his views became more religious, increasingly Lincoln focused on the centrality of ending slavery, which today is seen as a civil rights issue but then was seen by most abolitionists first as a spiritual issue, because slave-holding was an abomination before God.