This paper addresses the foundations of the Church systematically as it originates in the Triune God's plan of salvation. The Church is an extension of the missions of the Son and Spirit in history. Analogies are invoked to help ground the nature and the mission of the of the Church. The paper further explores the implications of Ecclesia de Trinitate in light of Vatican II, the visible and invisible missions of the Son and the Spirit, the role of Mary and the multi‐religious context.