See http://www.quakersintheworld.org/quakers-in-action/62/John-Woolman and the attached article, The First Person in Antislavery Literature: John Woolman, his Clothes and his Journal (Geoffrey Plank 2009)

Abstract: In his lifetime John Woolman (1720–1772) drew attention to himself with his unusual behavior, his expressive demeanor and his clothes. He sought to become a ‘sign’ directing others toward a way of life without exploitation or slavery. After his death and the publication of his journal, he was celebrated as the most important figure in the campaign to turn the Quakers against slaveholding. Woolman's self-presentation, contemporary responses to him, and the posthumous commemoration of him provide an indication of the power and significance of personal narrative within Quakerism and in antislavery politics in Britain and America.