His realism also helped when he faced sharp attacks. James Boswell, famed now for his biography of Samuel Johnson, wrote of Wilberforce, "I hate your little whittling sneer/ Your pert and self-sufficient leer begone, for shame/ Thou dwarf with big resounding name." (Wilberforce stood only 5 feet tall.) But Wilberforce did not respond in kind. Instead of speaking of his own accomplishments, he often said that one line of prayer summarized his only hope: "God be merciful to me a sinner."
Wilberforce emphasized teaching about Christianity but not imposing it, and wrote that Christians should "boldly assert the cause of Christ in an age when so many who bear the name of Christian are ashamed of Him. Let them be active, useful, and generous toward others. Let them show moderation and self-denial themselves. Let them be ashamed of idleness. When blessed with wealth, let them withdraw from the competition of vanity and be modest, retiring from ostentation, and not be the slaves of fashion."
He proceeded boldly but not arrogantly, knowing that he could commend belief but not command it. He stated, "the national difficulties we face result from the decline of religion and morality among us. I must confess equally boldly that my own solid hopes for the well-being of my country depend, not so much on her navies and armies as on the persuasion that she still contains many who love and obey the Gospel of Christ. I believe that their prayers may yet prevail."