Catechism of the Catholic Church §1176 — excerpt
The celebration of the Liturgy of the Hours demands not only harmonizing the voice with the praying heart, but also a deeper "understanding of the liturgy and of the Bible, especially of the Psalms."
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 90