Catechism of the Catholic Church §617 — excerpt
The Council of Trent emphasizes the unique character of Christ's sacrifice as "the source of eternal salvation" and teaches that "his most holy Passion on the wood of the cross merited justification for us."
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: Council of Trent: DS 1529 · LH, Lent, Holy Week, Evening Prayer, Hymn Vexilla Regis