2. A second aspect is that Mary’s faith gave human flesh to Jesus. As the Council says: “Through her faith and obedience, she gave birth on earth to the very Son of the Father, without knowing man but by the overshadowing of the Holy Spirit” (Lumen Gentium, 63). This was a point on which the Fathers of the Church greatly insisted: Mary first conceived Jesus in faith and then in the flesh, when she said “yes” to the message God gave her through the angel. What does this mean? It means that God did not want to become man by bypassing our freedom; he wanted to pass through Mary’s free assent, through her “yes”. He asked her: “Are you prepared to do this?” And she replied: “Yes”.

But what took place most singularly in the Virgin Mary also takes place within us, spiritually, when we receive the word of God with a good and sincere heart and put it into practice. It is as if God takes flesh within us; he comes to dwell in us, for he dwells in all who love him and keep his word. It is not easy to understand this, but really, it is easy to feel it in our heart.

Do we think that Jesus’ incarnation is simply a past event which has nothing to do with us personally? Believing in Jesus means giving him our flesh with the humility and courage of Mary, so that he can continue to dwell in our midst. It means giving him our hands, to caress the little ones and the poor; our feet, to go forth and meet our brothers and sisters; our arms, to hold up the weak and to work in the Lord’s vineyard, our minds, to think and act in the light of the Gospel; and especially to offer our hearts to love and to make choices in accordance with God’s will. All this happens thanks to the working of the Holy Spirit. And in this way we become instruments in God’s hands, so that Jesus can act in the world through us.

https://www.vatican.va/content/francesco/en/speeches/2013/october/documents/papa-francesco_20131012_preghiera-mariana.html