Abraham Lincoln grew up in a highly religious Baptist family. He never joined any Church, and was a skeptic as a young man and sometimes ridiculed revivalists. He frequently referred to God and had a deep knowledge of the Bible, often quoting it. Lincoln attended Protestant church services with his wife and children. "Especially after the death of his young son Willie in 1862, Lincoln moved away from his earlier religious skepticism."Foner, Eric, The Fiery Trial: Abraham Lincoln and American Slavery, New York and London: W. W. Norton and Company, 2010, p. 327. Some argue that Lincoln was neither a Christian believer nor a secular freethinker.

Although Lincoln never made an unambiguous public profession of Christian belief, several people who knew him personally, such as Chaplain of the Senate Phineas Gurley and Mary Todd Lincoln, claimed that he believed in Christ in the religious sense. Quoting Phineas Gurley. Noah Brooks to J. A. Reed, December 31, 1872. However, others who had known Lincoln for years, such as Ward Hill Lamon and William Herndon, rejected the idea that he was a believing Christian. During his 1846 run for the House of Representatives, in order to dispel accusations concerning his religious beliefs, Lincoln issued a handbill stating that he had "never denied the truth of the Scriptures". He seemed to believe in an all-powerful God, who shaped events and, by 1865, was expressing those beliefs in major speeches.

Before presidency Lincoln's parents were "Hard Shell" Baptists, joining the Little Pigeon Baptist Church near Lincoln City, Indiana, in 1823 when Abraham was 14 years old. Some writers have detected early Catholic influence on the young Lincoln which they attribute to his first school-teacher, Zachariah Riney.

In 1831, Lincoln moved to New Salem, which had no churches. Historian Mark Noll states that "Lincoln never joined a church nor ever made a clear profession of standard Christian belief." Noll quotes Lincoln's friend Jesse Fell:

Noll argues that Lincoln was turned against organized Christianity by his experiences as a young man witnessing how excessive emotion and bitter sectarian quarrels marked yearly camp-meetings and the ministry of traveling preachers. As a young man, Lincoln enjoyed reading the works of Thomas Paine. He drafted a pamphlet incorporating such ideas, but did not publish it. After charges of hostility to Christianity almost cost him a congressional bid, he kept his unorthodox beliefs private.Radicals in Their Own Time Michael Anthony Lawrence - 2010 p. 69 The one aspect of his parents' Calvinist religion that Lincoln apparently embraced wholeheartedly throughout his life was the "doctrine of necessity", also known as predestination, determinism, or fatalism. 29 pars. It was almost always through these lenses that Lincoln assessed the meaning of the Civil War.

James Adams (1783–1843) labeled Lincoln as a deist. It has been reported that in 1834 Lincoln wrote a manuscript essay challenging orthodox Christianity and modeled on Paine's book The Age of Reason. A friend supposedly burned the manuscript to protect Lincoln from ridicule. Biographer Rev. William Barton finds it likely that Lincoln had written an essay something of this character, but unlikely that it was burned in such a manner. New Salem schoolteacher Mentor Graham, with whom Lincoln boarded, reported in 1874 that the manuscript was "a defense of universal salvation".

William J. Herndon first published an account of the Paine-influenced manuscript in his 1889 biography of Lincoln. Harvey Lee Ross, mail carrier who lived in New Salem with Lincoln in 1834, regarded Herndon's account as a fictional story. He stated the following issues with the Herndon's account: Herndon was 16 years old in 1834 and lived 20 miles away in Springfield and did not have contact with Lincoln. There was no stove in Samuel Hill's store in 1834 where the manuscript was allegedly burned. There was not a copy of The Age of Reason on the bookshelf at the tavern where Herndon said Lincoln had read it. Finally, Ross stated he was very well acquainted with everyone in the community of New Salem and he would have known about any conversations regarding a document of this nature.Rufus Rockwell Wilson (1946). Lincoln's First Years In Illinois, The Primavera Press, Inc, NY. pp.51-53. It is a reasonable conclusion that there was never a manuscript written and Paine was not a contributing factor in Lincoln's ideas about religion.

William J. Johnson records a comment:

Noll writes, "At least early on, Lincoln was probably also a Universalist who believed in the eventual salvation of all people."

Lincoln was often perplexed by the attacks on his character by way of his religious choices. In a letter written to Martin M. Morris in 1843, Lincoln wrote:

In 1846, when Lincoln ran for Congress against Peter Cartwright, the noted evangelist, Cartwright tried to make Lincoln's religion or lack of it a major issue of the campaign. Responding to accusations that he was an "infidel", Lincoln defended himself, publishing a hand-bill to "directly contradict" the charge made against him. The declaration was released as follows:

As Carl Sandburg recounts in Abraham Lincoln: The Prairie Years (1926), Lincoln attended one of Cartwright's revival meetings. At the conclusion of the service, the fiery pulpiteer called for all who intended to go to heaven to rise. Naturally, the response was heartening. Then, he called for all those who wished to go to hell to stand. Unsurprisingly there were not many takers. Lincoln had responded to neither option. Cartwright closed in. "Mr. Lincoln, you have not expressed an interest in going to either heaven or hell. May I enquire as to where you do plan to go?" Lincoln replied: "I did not come here with the idea of being singled out, but since you ask, I will reply with equal candor. I intend to go to Congress."

William Herndon, Lincoln's law partner, stated that Lincoln admired deists Thomas Paine and Voltaire. Herndon, an advocate of Darwin, said Lincoln thought the works of authors like Darwin and Spencer "entirely too heavy for an ordinary mind to digest" but he read and was "interested ... greatly" in a book expounding on these ideas, "Vestiges of Creation", and he was "deeply impressed with the notion of the so-called 'universal law' — evolution ... and he became a warm advocate of the new doctrine."

Lincoln believed in God, but some said he doubted the idea that Christ is God. In a written statement to Herndon, James W. Keyes said Lincoln

believed in a Creator of all things, who had neither beginning nor end, who possessing all power and wisdom, established a principal, in Obedience to which, Worlds move and are upheld, and animel and vegatable life came into existence. A reason he gave for his belief was, that in view of the Order and harmony of nature which all beheld, it would have been More miraculouis to have Come about by chance, than to have been created and arranged by some great thinking power.

Keyes also added that Lincoln once said

As to the christian theory, that, Christ is God, or equal to the Creator he said had better be taken for granted — for by the test of reason all might become infidels on that subject, for evidence of Christs divinity Came to us in somewhat doubtful Shape — but that the Sistom of Christianity was an ingenious one at least — and perhaps was Calculated to do good.

During his White House years, Lincoln and his family often attended the New York Avenue Presbyterian Church, where a plaque marks the family pew he rented.

First Inaugural Address

On Monday, March 4, 1861, Lincoln delivered his first inaugural address, after the oath of office was administered by Chief Justice Roger Taney. Lincoln's speech addressed the national crisis of the southern secession from the union. Lincoln had hoped to resolve the conflict peacefully without a civil war. During the address, Lincoln stated, "Intelligence, patriotism, Christianity, and a firm reliance on Him who has never yet forsaken this favored land are still competent to adjust in the best way all our present difficulty."

Civil War In 1862 and 1863, during the most difficult days of the Civil War and his presidency, Lincoln's utterances were sometimes marked with spiritual overtones.

1862: Bereavement and Emancipation

On Thursday, February 20, 1862, at 5:00 p.m., Lincoln's eleven-year-old son, William Wallace Lincoln ("Willie"), died at the White House. Historians suggest that this may have been the most difficult personal crisis in Lincoln's life. After the funeral, he attempted a return to his routine but was unable. One week after the funeral, he isolated himself in his office and wept all day. Several people reported that Lincoln told them that his feelings about religion changed at this time. Willie is reported to have often remarked that he wanted to become a minister.

When his son died, Lincoln reportedly said, "May God live in all. He was too good for this earth. The good Lord has called him home. I know that he is much better off in Heaven." Lincoln quoted by Elizabeth KeckleyThis transformation is reported by a considerable number of contemporaries, and a number of scholars agree, though there is less agreement on the nature of this change. Pulitzer prize historian David H. Donald, Lincoln (Simon & Schuster, 1995), pp. 336-337, writes: "After the burial the President repeatedly shut himself in a room so that he could weep alone... During this time he increasingly turned to religion for solace... During the weeks after Willie's death Lincoln had several long talks with the Rev. Phineas D. Gurley, pastor of the New York Avenue Presbyterian Church in Washington where the Lincolns rented a pew... [W]hen he looked back on the events of this tragic spring, recognized that he underwent what he called 'a process of crystallization' in his religious beliefs." Ronald White, Lincoln's Greatest Speech (Simon & Schuster, 2002), p. 134, writes, "Many have pointed to the death of Willie on February 20, 1862, as a critical moment in Lincoln's struggles with faith." Stephen Oates, With Malice Toward None: A Life of Abraham Lincoln (Harper & Row, 1977), p. 70, writes, "After Willie's death, he talked more frequently about God than he had before." Sandburg, Abraham Lincoln: The War Years, III:379-380, recounts a report that "Mr. Lincoln's views in relation to spiritual things seemed changed from that hour [viz., Willie's death]."

Spiritualism, popularly in vogue during this era, was tried by Lincoln's wife. She used the services of mediums and spiritualists to try to contact their dead son. Lincoln allegedly attended at least one seance at the White House at this time with his wife.

When Bishop Matthew Simpson gave the address at Lincoln's funeral he quoted him asking a soldier "Do you ever find yourself talking with the dead? Since Willie's death, I catch myself every day, involuntarily talking with him as if he were with me."

At the same time, the war was not going well for the Union. General George McClellan's failure in the Peninsula Campaign came about within months after Willie's death. Next came Robert E. Lee's impressive victory at the Second Battle of Bull Run, after which he said, "I have been driven many times upon my knees by the overwhelming conviction that I had nowhere else to go."citing Noah Brooks article in Harper's Monthly, July 1865David H. Donald, Lincoln (Simon & Schuster, 1995), 354, writes, "By the summer of 1862, Lincoln felt especially in need of divine help. Everything, it seemed, was going wrong, and his hope for bringing a speedy end to the war was dashed."