Catechism of the Catholic Church §1120 — excerpt
The ordained ministry or ministerial priesthood is at the service of the baptismal priesthood. The ordained priesthood guarantees that it really is Christ who acts in the sacraments through the Holy Spirit for the Church.
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.
Also cites: LG 10 # 2