Catechism of the Catholic Church §955 — excerpt
"So it is that the union of the wayfarers with the brethren who sleep in the peace of Christ is in no way interrupted, but on the contrary, according to the constant faith of the Church, this union is reinforced by an exchange of spiritual goods."
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 49