From Fr Mead's sermon on the Eve of the Annunciation in 2001:
At Saint Thomas we have great respect for the holy season of Lent. We do not interrupt the Lenten observances of each day or the use of Lenten colors lightly. Only two feasts suffice to break the pattern. The feast of Saint Joseph on March 19 is one. The feast of the Annunciation of our Lord Jesus Christ to the Blessed Virgin Mary... is the other.
The Annunciation is very important, because it is the actual beginning of our Lord Jesus Christ’s life in the flesh. The Church calendar places the Annunciation exactly nine months before the date of Christ’s birth, from March 25 to December 25, so we see that the Annunciation is the moment of Jesus Christ’s conception as a human being in the womb of his mother Mary. ¬†
Read the rest of Fr Mead's 2001 sermon here.
You might also want to read or listen to Fr Austin's sermon on the line from the Apostles' Creed: "who was conceived by the Holy Ghost, born of the Virgin Mary."
We beseech thee, O Lord, pour thy grace into our hearts, that we who have known the incarnation of thy Son Jesus Christ, announced by an angel to the Virgin Mary, may by his cross and passion be brought unto the glory of his resurrection; who liveth and reigneth with thee, in the unity of the Holy Spirit, one God, now and for ever. Amen.
The Eve of the Annunciation