Catechism of the Catholic Church
e. Para. 797: "What the soul is to the human body, the Holy Spirit is to the Body of Christ, which is the Church" (St. Augustine, Sermo 267, 4: PL 38, 1231D). "To this Spirit of Christ, as an invisible principle, is to be ascribed the fact that all parts of the body are joined one with the other and with their exalted head; for the whole Spirit of Christ is in the head, the whole Spirit is in the body, and the whole Spirit is in each of the members" (Pius XII, encyclical Mystici Corporis: DS 3808).
Para. 798: The Holy Spirit is "the principle of every vital and truly saving action in each part of the Body" (Pius XII, encyclical, Mystici Corporis: DS 3808).
Para. 809: The Church is the Temple of the Holy Spirit. The Spirit is the soul, as it were, of the Mystical Body, the source of its life, of its unity in diversity, and of the riches of its gifts and charisms.