Lutheranism fully affirms the doctrine of the Trinity as expressed in the Nicene and Athanasian Creeds. The Augsburg Confession (Articles I and III) confesses one divine essence in three persons—Father, Son, and Holy Spirit—equal in power, eternity, and majesty. The Book of Concord explicitly endorses all three ecumenical creeds as faithful summaries of biblical teaching.

Luther himself wrote the Smalcald Articles (1536) declaring the doctrine of the Trinity non-negotiable. The Large Catechism expounds the roles of the three persons in creation, redemption, and sanctification. Lutheran theology understands the Trinity as the necessary framework for understanding salvation: the Father elects, the Son atones, and the Spirit applies grace through Word and Sacrament.