Catechism of the Catholic Church §1518 — excerpt
Word and sacrament form an indivisible whole. the Liturgy of the Word, preceded by an act of repentance, opens the celebration. the words of Christ, the witness of the apostles, awaken the faith of the sick person and of the community to ask the Lord for the strength of his Spirit.
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.