William Wilberforce was born in 1759 in Hull, in Yorkshire, the son of a wealthy merchant family, and he entered Parliament at twenty-one, a brilliant young man with a fine voice and a gift for friendship, including the friendship of the future prime minister, William Pitt. For a few years he was little more than a charming and ambitious politician. Then, in his middle twenties, he underwent the deep evangelical conversion he called the Great Change, and it turned his whole life around. He thought at first that a serious Christian must leave the dirty world of politics for the church, but the old slave-trader turned hymn-writer John Newton, the author of "Amazing Grace," counseled him to stay where God had placed him and serve from there. In 1787 Wilberforce wrote in his diary the sentence that became his life: "God Almighty has set before me two great objects, the suppression of the Slave Trade and the Reformation of Manners."

The slave trade was the engine of the empire's wealth, defended by planters and merchants and the inertia of a whole nation that profited from it. Wilberforce took it on, and in 1789, rising in the House of Commons, he refused to point the finger at any one party and laid the guilt on the whole nation, himself included: "I mean not to accuse any one, but to take the shame upon myself, in common, indeed, with the whole parliament of Great Britain, for having suffered this horrid trade to be carried on under their authority." "We are all guilty," he told them. Year after year he brought his motion, and year after year it was defeated. For twenty years he persisted, gathering the evidence, enduring the mockery and the delay, until in 1807 Parliament at last abolished the slave trade throughout the British Empire.

It was a victory, but not the victory. The trade was ended; slavery itself, the holding of human beings as property, went on. Wilberforce, his health failing, fought on for that greater abolition, and lived just long enough to see it come. In July of 1833, on his deathbed, he heard that the passage of the bill to abolish slavery through the Empire was at last assured; he died three days later, and the act became law that summer. He had given forty-six years to the cause, from his first resolve to his last breath.

Alongside the great campaign he wrote a book, A Practical View of Real Christianity, urging his comfortable countrymen that faith was not a respectable Sunday opinion but a fire in the heart that must burn out into action; and with his friends of the Clapham Sect, the network of praying reformers his enemies mocked as "the Saints," he labored at a hundred works of mercy and reform. He was no plaster saint, and on some questions of his day he was cautious and conservative. But on the one great question he never wavered, and he spent himself utterly upon it. He is the enduring proof that a Christian in public life can change the world, not by seizing power but by refusing, for half a lifetime, to stop asking it to do right.