In Philadelphia's historic Christ Church, hallowed by the graves of Benjamin Franklin and six other Founding Fathers, a community chastened by the Civil War's grievous losses came together to erect a memorial to a father and his soldier son, setting an example for the city on whom to honor and how.

Eight months after Robert E. Lee's surrender, a large group gathered in Christ Church for the dedication of a memorial to Capt. William White Dorr, a Union soldier they honored as "a Christian and a Patriot, 'Faithful unto death.' " In 1869, members of the congregation added a memorial to their rector, the Rev. Benjamin Dorr, father of the slain captain.

Founded in 1695, Christ Church is popularly venerated as "the Nation's Church" because many of the nation's founders, including George Washington, worshiped there while Philadelphia was the capital of the United States. During the Civil War, it was the Rev. Dorr's task to hold his fractious congregation together, without sacrificing his antislavery principles. The church's congregants, like Americans across the country, were furiously divided over slavery.

Among them were some of Pennsylvania's leading Republicans and the founders of the Union League, who did much to support President Abraham Lincoln, emancipation, and the enlistment and training of black soldiers in Union forces. Others returned to the slave states from which their families had come and joined the Confederacy. There were pro-slavery Copperhead Democrats who opposed Lincoln's prosecution of the war — and the Emancipation Proclamation. Church members Charles Ingersoll and John Christian Bullitt, both prominent lawyers, helped found Philadelphia's Central Democratic Club, established during the war to defend the proposition that "in the State of Pennsylvania, all power is inherent in the White People."

The Rev. Dorr supported Lincoln and the war for the Union and emancipation, and Will volunteered as an officer with the 121st Regiment of Pennsylvania Volunteers. As one congregant later recalled, Will Dorr "raised a company of young friends … and with [his] father's and [his] pastor's God speed proceeded to the field." His regiment's sacrificial stand at Gettysburg (68 percent casualties) was pivotal in the fight for the Union's preservation. In April 1864, grimly preparing for the Wilderness campaign in Virginia, he wrote: "If we were all to follow out the homely rule contrasting our lot with those who are worse off, it might often render the discontented spirit content." He was killed at 26 years of age, shot through the heart on May 10, 1864, while leading the regiment's assault on Confederate troops atop Laurel Hill at Spotsylvania Court House.

Dorr and his father stood with Lincoln. Both sides, Lincoln said in his Second Inaugural Address, "read the same Bible and pray to the same God, and each invokes His aid against the other." The greatest of presidents clearly abjured any moral equivalency between those sides, but summoned a charitable spirit of atonement and "malice toward none." This outraged many Northerners and astonished almost everyone, but he urged his compatriots to "strive on to finish the work we are in" — the deadly war against the rebellious Confederacy and against the national sin of racial bigotry — "with firmness in the right, as God gives us to see the right."

The Rev. Dorr endorsed the president's invocation of charity, even as he grieved the death of his son. "Let us welcome back, with open arms, those of our erring brethren, who sincerely desire to return to their first love," he preached to his congregants on the national "day of humiliation and mourning" after Lincoln's assassination. Dorr's supplicating call clearly depended on the submission of "erring brethren" to the cause that his son and millions of Union soldiers had so nobly advanced. "We feel," Dorr said, "that we have now a country, which we can call our own, united and strong, which will be for our children, and our children's children, an inalienable heritage." In using Jefferson's word inalienable from the Declaration of Independence, Dorr echoed the true American spirit that Lincoln resurrected at Gettysburg when he called for "a new nation, conceived in liberty, and dedicated to the proposition that all men are created equal."

More than 150 years later, it is up to us, ordinary Americans like the Dorrs, to validate that hopeful prophecy, to burnish again worthy memorials that America has too long ignored and nearly forgotten, and to strive on to finish the work we are in.

William F. Quigley Jr., a high school teacher of history for 30 years, is the author of "Pure Heart: The Faith of a Father and Son in the War for a More Perfect Union" (Kent State University Press).