Catechism of the Catholic Church §348 — excerpt
The sabbath is at the heart of Israel's law. To keep the commandments is to correspond to the wisdom and the will of God as expressed in his work of creation.
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.