""First Day Sabbath Not Of Divine Appointment"" is a book written by Henry Clarke Wright in 1846. The book explores the idea that the traditional Christian Sabbath, observed on Sundays, is not actually of divine appointment. Wright presents his argument by citing the opinions of various theologians and scholars, including John Calvin, Martin Luther, Thomas Belsham, Philip Melancthon, Robert Barclay, and William Paley. The book is a historical and...