Abraham Lincoln never spoke directly about being a Christian or a believer in any religion or sect. Even his closest friends never had a clear idea of Lincoln’s religious beliefs, even after his death.

Lincoln knew that his lack of religious affiliation was affecting his political career. Still, he continued with his seeming disinterest in publicly affiliating himself with any form of religion. He chose the harder path — he stayed true to himself and did not fake his sentiments just to meet other people’s expectations. 

Lincoln was raised by Baptist parents, but he did not undergo baptismal rites as a child or an adult. As a young man in his twenties, he began to speak freely about his doubts regarding religion. One Civil War historian says that Lincoln was assertive whenever he spoke about his doubts about commonly-held beliefs. As a result, people were sometimes stunned to hear his blunt views. However, age has tamed his wild words, and when he entered his thirties, he knew it was wiser to speak carefully about religion.

In 1843, Lincoln paid for his lack of passion for religion. He ran as a Whig candidate for the House of Representatives, and he failed. He knew that no Christian wanted to sympathize with him because he was not connected with any church. A few years later, a political critic and preacher named Peter Cartwright hurled an attack against his seeming lack of faith. Lincoln again had to remind himself not to speak openly about his religious skepticism. This time, he had to explain his views in a leaflet, saying that he never dismissed the contents of the Scriptures and that he never deliberately spoke harshly of any religion or any Christian group. Despite this, Lincoln still did not directly explain whether he indeed believed in Christian teachings. And he was probably right. In Lincoln’s most famous speeches, including the Gettysburg Address, the House Divided, and his second inaugural, he quoted from Scripture and made references to the general concept of Providence.

Even as a man in his fifties, he kept his religious sentiments largely to himself. However, serious events happened to him that changed him in some ways. His son, Edward, died in 1850, followed by the death of his other son, William Wallace. These profound losses forced Lincoln to think more seriously about religion. In 1861, the Civil War broke out, and this made him think that if there really was a God, then what might he be planning for the whole industry of slavery and for the nation itself. In 1862, he wrote that although there were two opposing sides in the Civil War, God’s plans may have been entirely different from what the two sides were fighting for.

Lincoln once shared his thoughts about God with his friend, Senator Orville Hickman Browning. He told the senator that God would not help the Union unless the Union fought to end slavery. Lincoln shared this thought with some more people, who were stunned to hear him talk about God in this way. They were used to not seeing him go to church, pray publicly, or discuss what God might want for the country. Once, during a cabinet meeting, Lincoln announced that he wanted to give out the Emancipation Proclamation. He was asked why he wanted to do this, and he said that he had promised his maker that if the Union army won over the Confederate army in Maryland, he would make the proclamation soon after. His cabinet members were shocked to hear Lincoln talk about God in this manner that one of them asked him to repeat what he said.

When the war ended, Lincoln wrote to a newspaper editor, expressing his belief in a God that controlled events that were beyond the comprehension of humans. He asserted that he had no control over the events that transpired during the war and that, instead, he was controlled by events. And now, he said, only God would eventually reveal what evils should be removed and who should be held responsible for those evils.

After Lincoln’s assassination in 1865, his wife, Mary Todd Lincoln, answered difficult questions about his late husband’s religious beliefs. Consequently, she gave some answers about what Lincoln believed, but some of her answers conflicted with her other answers.

Lincoln may have told his friends that God wanted to end slavery, but they said that they did not have a clear idea of what Lincoln’s beliefs really were. They said he was too distant when it came to intimate conversations about God and Christianity.

Some historians say that Lincoln’s second inaugural address contained more spirituality than any of his other speeches. In this speech, Lincoln expressed that the war’s causes and its results were part of God’s plan for the nation. In his old age, he started to use more words that reflected religious imagery. While this may only be a sign of political maturity and a way of reaching a wider audience, it may also have been a sign of his changing personal beliefs. There is one account that says on the day of his assassination; Lincoln told his wife he wanted to visit the Holy Land.

Today, scholars and historians are in a much more difficult position to imagine what Lincoln really believed. In spite of his aloofness on religious matters, his Bible has perhaps the most enigmatic appeal of all U.S. presidents’. He swore by it during his inauguration, and Donald Trump and Barack Obama swore by it during theirs.