Catechism of the Catholic Church §424 — excerpt
' On the rock of this faith confessed by St. Peter, Christ built his Church. "To preach. . the unsearchable riches of Christ"
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.
Whole chapters cited: Matthew 51 · Matthew 62 · Matthew 83
Also cites: St. Leo the Great, Sermo 4 3: PL 54,150 - 152 · Matthew 1: PL 54 · Matthew 2: PL 54 · Matthew 3: PL 54