In CCC 1857, there is a quotation of the three requirements for a mortal sin. The quotation is listed in the footnotes as RP 17 § 12. What is “RP”?
Reconciliatio et paenitentia (Reconciliation & Penance), Apostolic Exhortation of St. John Paul II.
FYI, all the abbreviations for the Catechism are at the front of the book. Or if you’re using the online version, visit this page.
Here’s the cited paragraph, if you are interested (12th paragraph of the 17th article):
Here we have the core of the church’s traditional teaching, which was reiterated frequently and vigorously during the recent synod. The synod in fact not only reaffirmed the teaching of the Council of Trent concerning the existence and nature of mortal and venial sins,(95) but it also recalled that mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent. It must be added-as was likewise done at the synod-that some sins are intrinsically grave and mortal by reason of their matter. That is, there exist acts which, per se and in themselves, independently of circumstances, are always seriously wrong by reason of their object. These acts, if carried out with sufficient awareness and freedom, are always gravely sinful.(96)
Cf Council of Trent, Session VI, De Iustificatione, Chap. 2 and Canons 23, 25, 27: Conciliorum Oecumenicorum Decreta, Bologna 1973, 671 and 680f (DS 1573, 1575,1577).
Cf Council of Trent, Session IV De Iustificatione, Chapt. 15: Conciliorum Oecumenicorum Decreta, ed. dt. 677 (DS 1544).
There’s more footnotes to follow there, too.
Wow, Joe, thanks! I had no idea this went all the way back to Trent. Awesome.