Catechism of the Catholic Church §367 — excerpt
Sometimes the soul is distinguished from the spirit: St. Paul for instance prays that God may sanctify his people "wholly", with "spirit and soul and body" kept sound and blameless at the Lord's coming.
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 Constantinople IV (870): DS 657 · Vatican Council I, Dei Filius: DS 3005 · GS 22 # 5 · Humani generis: DS 3891