While often caricatured as severe and inflexible, Calvin’s theology in the Institutes in fact builds on the reformer’s own reverence and love for God revealed in Jesus Christ. Dennis Ngien shows how Calvin’s theology of piety shapes his wider theological ideas, including divine revelation, providence, justification and sanctification, adoption in Christ, prayer, and the purpose of the church. By closely expositing the Institutes, Ngien demonstrates how the triune God is crucial to everything: the Holy Spirit gifts believers their relationship with the Father through God’s Son, Jesus Christ, in whose life they find their own lives and the guarantee of their heavenly inheritances. Thus, Calvin’s Trinitarian theology engenders in believers a piety focused not on self-fulfillment but on loving God as Father and fearing God as Lord.