58 In the parable of the sower, Saint Luke has left us these words of the Lord about the "good soil": "These are the ones who when they hear the word, hold it fast in an honest and good heart, and bear fruit with patient endurance" ( Lk 8:15). In the context of Luke’s Gospel, this mention of an honest and good heart which hears and keeps the word is an implicit portrayal of the faith of the Virgin Mary. The evangelist himself speaks of Mary’s memory, how she treasured in her heart all that she had heard and seen, so that the word could bear fruit in her life. The Mother of the Lord is the perfect icon of faith; as Saint Elizabeth would say: "Blessed is she who believed" ( Lk 1:45). In Mary, the Daughter of Zion, is fulfilled the long history of faith of the Old Testament, with its account of so many faithful women, beginning with Sarah: women who, alongside the patriarchs, were those in whom God’s promise was fulfilled and new life flowered. In the fullness of time, God’s word was spoken to Mary and she received that word into her heart, her entire being, so that in her womb it could take flesh and be born as light for humanity. Saint Justin Martyr, in his dialogue with Trypho, uses a striking expression; he tells us that Mary, receiving the message of the angel, conceived "faith and joy". In the Mother of Jesus, faith demonstrated its fruitfulness; when our own spiritual lives bear fruit we become filled with joy, which is the clearest sign of faith’s grandeur. In her own life Mary completed the pilgrimage of faith, following in the footsteps of her Son. In her the faith journey of the Old Testament was thus taken up into the following of Christ, transformed by him and entering into the gaze of the incarnate Son of God.
Source: Lumen Fidei (Vatican.va)