Sources: Calvin, Institutes of the Christian Religion (1536, final edition 1559); Calvin, Commentaries; the Heidelberg Catechism (1563); the Westminster Confession (1647); the Synod of Dort (1618–19, TULIP).

Reformed/Calvinist theology is the systematic theological tradition developed by John Calvin (~1509–1564 AD) in Geneva and extended by his successors. Calvin’s theological distinctives: (1) The sovereignty of God — the organizing principle of all Reformed theology; God’s eternal decrees encompass all events including salvation and reprobation; (2) Double predestination — God elects some to salvation and passes over others (reprobation); this is Calvin’s logical extension of Augustine; (3) The covenant structure — Calvin develops covenant theology (federal theology) to explain the relationship between the Old and New Testaments and between God and humanity; (4) Regulative principle of worship — only what Scripture explicitly commands is permitted in worship (vs. Lutheran normative principle: what Scripture doesn’t forbid is permitted); (5) TULIP — the five points of Calvinism codified at Dort: Total depravity, Unconditional election, Limited atonement, Irresistible grace, Perseverance of the saints. The Reformed tradition produced: Presbyterianism, Congregationalism, the Puritans, the Dutch Reformed churches, and strong influence on Anglicanism. The Westminster Confession (1647) is the most comprehensive confessional statement of Reformed theology. Calvinism’s cultural influence — through the “Protestant work ethic” (Weber), covenantal democracy, and New England Puritanism — on Western political and economic culture is profound.