CCC 1031
© Libreria Editrice Vaticana Source: vatican.va
The Church gives the name Purgatory to this final purification of the elect, which is entirely different from the punishment of the damned. Cf. Council of Florence (1439): DS — Denzinger–Schönmetzer (Enchiridion Symbolorum); Council of Trent (1563): DS — Denzinger–Schönmetzer (Enchiridion Symbolorum); (1547): 1580; see also Benedict XII, Benedictus Deus (1336): DS — Denzinger–Schönmetzer (Enchiridion Symbolorum). The Church formulated her doctrine of faith on Purgatory especially at the Councils of Florence and Trent. the tradition of the Church, by reference to certain texts of Scripture, speaks of a cleansing fire: Cf. 1 Cor 3:15; 1 Pet 1:7.
As for certain lesser faults, we must believe that, before the Final Judgment, there is a purifying fire. He who is truth says that whoever utters blasphemy against the Holy Spirit will be pardoned neither in this age nor in the age to come. From this sentence we understand that certain offenses can be forgiven in this age, but certain others in the age to come. St. Gregory the Great, Dial. 4, 39: PL — Patrologia Latina (Migne); cf. Mt 12:31.
Read the full chapter 3. I Believe in the Holy Spirit ¶683–1065