Catechism of the Catholic Church §457 — excerpt
The Word became flesh for us in order to save us by reconciling us with God, who "loved us and sent his Son to be the expiation for our sins": "the Father has sent his Son as the Saviour of the world", and "he was revealed to take away sins":
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: St. Gregory of Nyssa, Orat. catech 15: PG 45, 48B
