Catechism of the Catholic Church §1098 — excerpt
The assembly should prepare itself to encounter its Lord and to become "a people well disposed." the preparation of hearts is the joint work of the Holy Spirit and the assembly, especially of its ministers.
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.