Catechism of the Catholic Church §2747 — excerpt
Christian Tradition rightly calls this prayer the "priestly" prayer of Jesus. It is the prayer of our high priest, inseparable from his sacrifice, from his passing over (Passover) to the Father to whom he is wholly "consecrated."
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.