Catechism of the Catholic Church §494 — excerpt
At the announcement that she would give birth to "the Son of the Most High" without knowing man, by the power of the Holy Spirit, Mary responded with the obedience of faith, certain that "with God nothing will be impossible": "Behold, I am the handmaid…
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.
Whole chapters cited: Luke 56
Also cites: LG 56 · St. Irenaeus, Adv. haeres. 3, 22, 4: PG 7/1, 959A · St. Epiphanius, Panarion 2, 78, 18: PG 42, 728CD-729AB · St. Jerome, Ep. 22, 21: PL 22, 408