Catechism of the Catholic Church

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. The Church teaches that this distinction does not introduce a duality into the soul. "Spirit" signifies that from creation man is ordered to a supernatural end and that his soul can gratuitously be raised beyond all it deserves to communion with God. (2083)