Catechism of the Catholic Church §1969 — excerpt
The New Law practices the acts of religion: almsgiving, prayer and fasting, directing them to the "Father who sees in secret," in contrast with the desire to "be seen by men."
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 16 · Matthew 17 · Matthew 18