"Let your life speak" is Quaker shorthand for the primacy of practice over profession, and the testimonies — simplicity, peace, integrity, community, equality, stewardship — are the practical form. Historically this produced concrete results out of proportion to the group's size: Friends were early and organized abolitionists, prison reformers, and campaigners for women's equality, and the Quaker refusal to swear oaths (since it implies a double standard of truthfulness) reached the point of changing English law.