Catechism of the Catholic Church §2751 — excerpt
Finally, in this prayer Jesus reveals and gives to us the "knowledge," inseparably one, of the Father and of the Son, which is the very mystery of the life of prayer.
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.