Catechism of the Catholic Church §686 — excerpt
The Holy Spirit is at work with the Father and the Son from the beginning to the completion of the plan for our salvation. But in these "end times," ushered in by the Son's redeeming Incarnation, the Spirit is revealed and given, recognized and welcomed as a person.
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.