Catechism of the Catholic Church §711 — excerpt
"Behold, I am doing a new thing." Two prophetic lines were to develop, one leading to the expectation of the Messiah, the other pointing to the announcement of a new Spirit.
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.