Peculiar Doctrines, Public Morals, and the Political Welfare – Excerpted introduction from a biography on the life of William Wilberforce by John Piper
“If you want to understand and appreciate The Life and Labor of William Wilberforce, one of the wisest things you can do is to read his own book, A Practical View of Christianity first, and then read biographies. The book was published in 1797 when Wilberforce was 37 years old and had been a member of the British Parliament already for 16 years. The book proved incredibly popular for the time. It went through five printings in six months and was translated into five foreign languages. The book makes crystal clear what drives Wilberforce as a person and a politician. And if you don’t see it first in his book, chances are you may not find it clearly in the biographies.
What made Wilberforce tick was a profound Biblical allegiance to what he called the “peculiar doctrines” of Christianity. These, he said, give rise, in turn, to true affections – what we might call “passion” or “emotions” – for spiritual things, which, in turn, break the power of pride and greed and fear, and then lead to transformed morals which, in turn, lead to the political welfare of the nation. He said, “If . . . a principle of true Religion [i.e., true Christianity] should . . . gain ground, there is no estimating the effects on public morals, and the consequent influence on our political welfare.” 
But he was no ordinary pragmatist or political utilitarian, even though he was one of the most practical men of his day. He was a doer. One of his biographers said, “He lacked time for half the good works in his mind.”  James Stephen, who knew him well, remarked, “Factories did not spring up more rapidly in Leeds and Manchester than schemes of benevolence beneath his roof.”  “No man,” Wilberforce wrote, “has a right to be idle.” “Where is it,” he asked, “that in such a world as this, [that] health, and leisure, and affluence may not find some ignorance to instruct, some wrong to redress, some want to supply, some misery to alleviate?”  In other words, he lived to do good – or as Jesus said, to let his light shine before men that they might see his good deeds and give glory to his Father in heaven (Matthew 5:16).
But he was practical with a difference. He believed with all his heart that new affections for God were the key to new morals (or manners, as they were sometimes called) and lasting political reformation. And these new affections and this reformation did not come from mere ethical systems. They came from what he called the “peculiar doctrines” of Christianity. For Wilberforce, practical deeds were born in “peculiar doctrines.” By that term he simply meant the central distinguishing doctrines of human depravity, divine judgment, the substitutionary work of Christ on the cross, justification by faith alone, regeneration by the Holy Spirit, and the practical necessity of fruit in a life devoted to good deeds. 
He wrote his book, A Practical View of Christianity, to show that the “Bulk”  of Christians in England were merely nominal because they had abandoned these doctrines in favor of a system of ethics and had thus lost the power of ethical life and the political welfare. He wrote:
The fatal habit of considering Christian morals as distinct from Christian doctrines insensibly gained strength. Thus the peculiar doctrines of Christianity went more and more out of sight, and as might naturally have been expected, the moral system itself also began to wither and decay, being robbed of that which should have supplied it with life and nutriment.” 
He pled with nominally Christian England not to turn “their eyes from the grand peculiarities of Christianity, [but] to keep these ever in view, as the pregnant principles whence all the rest must derive their origin, and receive their best support.” 
Knowing Wilberforce was a politician all his adult life, never losing an election from the time he was 21 years old, we might be tempted to think that his motives were purely pragmatic – as if he should say, “if Christianity works to produce the political welfare, then use it.” But that is not the spirit of his mind or his life. In fact, he believed that such pragmatism would ruin the very thing it sought, the reformation of culture.
Take the example of how people define sin. When considering the nature of sin, Wilberforce said, the vast Bulk of Christians in England estimated the guilt of an action “not by the proportion in which, according to scripture, [actions] are offensive to God, but by that in which they are injurious to society.”  Now, on the face of it that sounds noble, loving, and practical. Sin hurts people, so don’t sin.
Wouldn’t that definition of sin be good for society? But Wilberforce says, “Their slight notions of the guilt and evil of sin [reveal] an utter [lack] of all suitable reverence for the Divine Majesty. This principle [reverence for the Divine Majesty] is justly termed in Scripture, ‘The beginning of wisdom’ [Psalm 111:10].”  And without this wisdom, there will be no deep and lasting good done for man, spiritually or politically. Therefore, the supremacy of God’s glory in all things is what he calls “the grand governing maxim” in all of life.  The good of society may never be put ahead of this. It dishonors God and defeats the good of society. For the good of society, the good of society must not be the primary good.
A practical example of how his mind worked would be the practice of dueling. Wilberforce hated the practice of dueling – the practice that demanded a man of honor to accept a challenge to a duel when another felt insulted. Wilberforce’s close friend and Prime Minister, William Pitt, actually fought a duel with George Tierney in 1798, and Wilberforce was shocked that the Prime Minister would risk his life and the nation in this way.  Many opposed it on its human unreasonableness. But Wilberforce wrote:
It seems hardly to have been noticed in what chiefly consists its essential guilt; that it is a deliberate preference of the favor of man, before the favor and approbation of God, in articulo mortis [“at the point of death”], in an instance, wherein our own life, and that of a fellow creature are at stake, and wherein we run the risk of rushing into the presence of our Maker in the very act of offending him.” 
In other words, offending God is the essential consideration, not killing a man or imperiling a nation. That is what makes Wilberforce tick. He was not a political pragmatist. He was a radically God-centered Christian who was a politician.