Several centuries after the words of the prophet Isaiah, as found in the first reading, were written down, the Gospel writer Luke, through the event of the annunciation, affirms that Jesus is the fulfilment of Isaiah's prophecy. For Luke, the annunciation of the birth of Jesus is the high point of all the Old Testament prophecies for it proves that nothing is impossible with God.

Indeed, the Solemnity of the Annunciation of the Lord reveals to Christians the greatest mystery of our faith and the true nature of the promised Messiah, that is, he is both human and divine. It also reveals what true faith is through the person of Mary. What the angel communicates to her is something truly extraordinary. Even so, she exercises the faith required on her part to accept the truth of it.

Therefore, Mary's response to God's call is full of trust and humility. Despite her faith, there is no doubt that the fulfilment of the promise might bring along with it a shame, reproach and even a death sentence as she was an unmarried woman. However, she did not allow her fears to deter her from humbly submitting herself to the will of God.

In accepting her physical motherhood as the mother of the Messiah, Mary assents to her spiritual motherhood for all humanity. As stated by the Second Vatican Council: "At the message of the angel, the Virgin Mary received the word of God in her heart and in her body, and gave life to the world" (Constitution on the Church, 53).