Catechism of the Catholic Church §678 — excerpt
Following in the steps of the prophets and John the Baptist, Jesus announced the judgement of the Last Day in his preaching. Then will the conduct of each one and the secrets of hearts be brought to light.
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: Joel 3 · Joel 4