Catechism of the Catholic Church §760 — excerpt
Christians of the first centuries said, "The world was created for the sake of the Church." God created the world for the sake of communion with his divine life, a communion brought about by the "convocation" of men in Christ, and this "convocation" is 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: Pastor Hermae, Vision 2, 4, 1: PG 2,899 · Aristides, Apol. 16, 6 · St. Justin, Apol. 2,7: PG 6, 456 · Tertullian, Apol. 31, 3 · 32, 1: PL 1, 508-509 · St. Epiphanius, Panarion 1, 1, 5: PG 41, 181C · Clement of Alex., Paed. 1, 6, 27: PG 8, 281