Catechism of the Catholic Church §1074 — excerpt
"The liturgy is the summit toward which the activity of the Church is directed; it is also the font from which all her power flows."
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.
Also cites: SC 10 · John Paul II, CT 23