Today, we commemorate 'The Annunciation of the Lord'. That a "maiden" will be "with child" and will "give birth to a son" was prophesied by Isaiah. The name to be given to the child is "Emmanuel" ("God-is-with-us" - Is.7:14). Matthew in his gospel (Matthew 1:23) quotes Isaiah 7:14. This lends credence that Jesus indeed is the "Emmanuel" prophesied by Isaiah; and that the "maiden" is Mary.
In the Gospel reading, the angel Gabriel announces to Mary that "the Lord is with you". Then Gabriel assures Mary that she is the chosen one of God to conceive and bear the "Son of the Most High". Her answer? "Let what you have said be done to me" In Mary's answer, the prophecy of Isaiah and the announcement of the angel will soon bear "fruit" in her womb, in the person of Jesus.
For God's will to be done - human consent is needed. David, who wrote Psalm 40 says, that God is not looking for our sacrifices or offerings; God is looking for "an open ear". An ear not deaf to God's call. Just as David said, "Here am I" (Ps. 40:7); Mary, her 'Yes' (Lk. 1:38); and Jesus, "God, here I am! I am coming to obey Your will," (Hebr. 10:7) - we too need to know when God speaks, and respond positively, when God calls.
Lord, grant me openness to listen with deep faith, so as to respond with joyful obedience all that You ask of me.