Catechism of the Catholic Church §1186 — excerpt
Finally, the church has an eschatological significance. To enter into the house of God, we must cross a threshold, which symbolizes passing from the world wounded by sin to the world of the new Life to which all men are called.
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.