In his 77 years, Frederick Douglass, America's most famous abolitionist, delivered thousands of speeches, wrote three autobiographies, started newspapers, met with President Abraham Lincoln, and championed the cause of African American civil rights. But most people downplay a crucial part of his life: his radical Christian faith.

The crucible of Douglass' prophetic Christian faith was his childhood suffering as a slave. Before his escape at age 20, Douglass witnessed and endured great cruelty, especially at the hands of Christian masters. He saw first-hand brutal whippings, cold-blooded murder, and the daily trials of physical and psychological abuse. He watched a slave master beat his aunt, a 15-year-old girl of striking beauty, nearly to death.

In 1826, Douglass was sent to Baltimore to live with Hugh and Sophia Auld. When he heard Sophia, a devout Christian, read from the Book of Job, Douglass decided he had to know more about this man Job—how he could say, despite his suffering, "blessed be the name of the Lord." He secretly taught himself to read. As a teenager, he formally converted to Christianity, shepherded by free black Methodists. Assurance of salvation came slowly, but once he cast all his cares upon God, Douglass wrote, he found faith in Christ as "Redeemer, Friend, and Savior."

In March 1833, Hugh Auld unexpectedly sent Douglass back to the Eastern Shore. For the next three years, Douglass worked as a field hand before escaping and settling in New Bedford, Massachusetts. By 1841 he was involved in the abolition movement. His task was to convince Americans to see the antislavery cause as a great moral necessity. To that end, he repeated a chastening refrain: "Between the Christianity of this land, and the Christianity of Christ, I recognize the widest possible difference."

For Douglass, the problem was not Jesus or Christianity; it was the hypocrisy of Christians. He condemned what he called the "corrupt, slaveholding, women-whipping, cradle-plundering, partial, and hypocritical Christianity" everywhere present in America. He blasted "the man who wields the blood-clotted cowskin during the week, fills the pulpit on Sunday, and claims to be a minister of the meek and lowly Jesus." He derided the slaveholder who "covers his infernal business with the garb of Christianity."

Like the Pharisees condemned by Jesus (in Matthew 23 and other places), slaveholders and their apologists "attend with Pharisaical strictness to the outward forms of religion, and at the same time neglect the weightier matters of the law, judgment, mercy, and faith." They had utterly abandoned the true Christianity of Christ and invited the wrath of a just and avenging God.