ecclesiology

Ecclesiology is the branch of Christian theology that examines the church—its nature, origin, purpose, and organization—and its relationship to God and the world. The term comes from the Greek ekklesia, “assembly.” Core questions include what the church is (a visible institution, a spiritual body, or both), how it is governed, how it administers the sacraments or ordinances, and what its mission entails in worship, proclamation, service, and social justice.

The church is often described by the four marks, drawn from the Nicene Creed: one, holy, catholic (universal), and apostolic. Different Christian traditions understand these marks in distinct ways. Catholic and Orthodox theology emphasize apostolic succession, liturgical sacraments, and continuity with the historic church, while Protestant and many Anglican traditions stress the reign of God proclaimed in Scripture, the priesthood of all believers, and varied forms of church government. Sacraments or ordinances (such as baptism and the Lord’s Supper) are central in many traditions, though their number and theology differ.

Ecclesiology also addresses the church’s mission: mirroring Christ in worship, teaching, and service; witnessing to the gospel; and participating in the world through social action and dialogue. In modern times, ecclesiology has engaged ecumenism, questions of church governance, debates over ministry and gender, and the idea of the church as sign and instrument of God’s Kingdom. The topic has evolved with historical developments from early Christian communities to contemporary global Christianity.