1560s, "opponent of Anglican hierarchy," later applied opprobriously to "person in Church of England who seeks further reformation" (1570s), probably from purity. Largely historical from 19c. in literal sense. After c. 1590s, applied to anyone deemed overly strict in matters of religion and morals.
What [William] Perkins, and the whole Puritan movement after him, sought was to replace the personal pride of birth and status with the professional's or craftsman's pride of doing one's best in one's particular calling. The good Christian society needs the best of kings, magistrates, and citizens. Perkins most emphasized the work ethic from Genesis: "In the swaete of thy browe shalt thou eate thy breade." [E. Digby Baltzell, "Puritan Boston and Quaker Philadelphia," 1979]