In a certain sense Mary lived her Eucharistic faith even before the institution of the Eucharist, by the very fact that she offered her virginal womb for the Incarnation of God’s Word. The Eucharist, while commemorating the passion and resurrection, is also in continuity with the incarnation. At the Annunciation Mary conceived the Son of God in the physical reality of his body and blood, thus anticipating within herself what to some degree happens sacramentally in every believer who receives, under the signs of bread and wine, the Lord’s body and blood.
As a result, there is a profound analogy between the Fiat which Mary said in reply to the angel, and the Amen which every believer says when receiving the body of the Lord. Mary was asked to believe that the One whom she conceived “through the Holy Spirit” was “the Son of God” (Lk 1:30-35). In continuity with the Virgin’s faith, in the Eucharistic mystery we are asked to believe that the same Jesus Christ, Son of God and Son of Mary, becomes present in his full humanity and divinity under the signs of bread and wine.
-Blessed John Paul II, Ecclesia de Eucharistia, par 55-
I write about this theme in Chapter 7 of Blessed, Beautiful, and Bodacious.