Completely imbued with the Word of God, Mary is able to become the Mother of the Word Incarnate

Outstanding among the saints is Mary, Mother of the Lord and mirror of all holiness. In the Gospel of Luke we find her engaged in a service of charity to her cousin Elizabeth, with whom she remained for “about three months” (1:56) so as to assist her in the final phase of her pregnancy. “Magnificat anima mea Dominum”, she says on the occasion of that visit, “My soul magnifies the Lord” (Lk 1:46). In these words she expresses her whole programme of life: not setting herself at the center, but leaving space for God, who is encountered both in prayer and in service of neighbor—only then does goodness enter the world. Mary's greatness consists in the fact that she wants to magnify God, not herself. She is lowly: her only desire is to be the handmaid of the Lord (cf. Lk 1:38, 48). She knows that she will only contribute to the salvation of the world if, rather than carrying out her own projects, she places herself completely at the disposal of God's initiatives. Mary is a woman of hope: only because she believes in God's promises and awaits the salvation of Israel, can the angel visit her and call her to the decisive service of these promises. Mary is a woman of faith: “Blessed are you who believed”, Elizabeth says to her (cf. Lk 1:45). The Magnificat—a portrait, so to speak, of her soul—is entirely woven from threads of Holy Scripture, threads drawn from the Word of God. Here we see how completely at home Mary is with the Word of God, with ease she moves in and out of it. She speaks and thinks with the Word of God; the Word of God becomes her word, and her word issues from the Word of God. Here we see how her thoughts are attuned to the thoughts of God, how her will is one with the will of God. Since Mary is completely imbued with the Word of God, she is able to become the Mother of the Word Incarnate.

Benedict XVI, encyclical Deus caritas est #41