Catechism of the Catholic Church §747 — excerpt
The Holy Spirit, whom Christ the head pours out on his members, builds, animates, and sanctifies the Church. She is the sacrament of the Holy Trinity's communion with men.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.