In 1864, Abraham Lincoln made a rare wartime trip out of Washington to visit a charity event in Philadelphia raising money to care for wounded soldiers. He donated 48 copies of the Emancipation Proclamation to be sold for fund-raising.

But it turns out he received a gift in return: a Bible whose pages were edged with gilt and decorated with the words “Faith,” “Hope” and “Charity” after I Corinthians 13:13 — a holy book at a time when Lincoln was turning increasingly to Scripture to understand personal tragedy and national trauma.

Now, more than 150 years later, historians have discovered the Bible for the first time, a unique artifact of the 16th president’s lifethat they did not even know existed. Given by his widow to a friend of Lincoln’s after his assassination, it has remained out of sight for a century and a half, passed along from one generation to another, unknown to the vast array of scholars who have studied his life.

As of Thursday, it will go on display for the first time at the Abraham Lincoln Presidential Library and Museum in Springfield, Ill., a bequest from the family of the Rev. Noyes W. Miner, who lived across the street from the Lincolns in the Illinois capital and spoke at the slain president’s funeral. After preserving the Bible over the decades, Miner’s descendants recently came forward to disclose its existence and donate it to the public.