Catechism of the Catholic Church §1359 — excerpt
The Eucharist, the sacrament of our salvation accomplished by Christ on the cross, is also a sacrifice of praise in thanksgiving for the 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.