Catechism of the Catholic Church §1133 — excerpt
The Holy Spirit prepares the faithful for the sacraments by the Word of God and the faith which welcomes that word in well-disposed hearts. Thus the sacraments strengthen faith and express it.
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.