Catechism of the Catholic Church §2753 — excerpt
In the battle of prayer we must confront erroneous conceptions of prayer, various currents of thought, and our own experience of failure. We must respond with humility, trust, and perseverance to these temptations which cast doubt on the usefulness or even the possibility of prayer.
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.