Catechism of the Catholic Church §823 — excerpt
"The Church . . is held, as a matter of faith, to be unfailingly holy. This is because Christ, the Son of God, who with the Father and the Spirit is hailed as 'alone holy,' loved the Church as his Bride, giving himself up for…
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.
Whole chapters cited: Acts 913 · 1 Corinthians 61 · 1 Corinthians 16
Also cites: LG 39 · LG 12