Catechism of the Catholic Church §148 — excerpt
The Virgin Mary most perfectly embodies the obedience of faith. By faith Mary welcomes the tidings and promise brought by the angel Gabriel, believing that "with God nothing will be impossible" and so giving her assent: "Behold I am the handmaid of the Lord; let it be [done] to me according to your word."
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.