Why was the annunciation important?

Answer 1

.

Catholic AnswerThe Annunication is nine months before Christmas. It is the solemnity in which Our Blessed Lord descended from heaven in order to become incarnate of the Virgin Mary, in other words, it is the conception of God on earth.

Answer 2

The Annunciation is so important because the angelGabriel toldMaryshe was going to have a Son, and that she would name HimJesusand He will be a holy and be the Son of God.

Catholic AnswerThe Annunciation was important because it was God intervening in human history to inaugurate the "fullness of time" which began at that moment and is what we currently live in.

from The Catechism of the Catholic Church, second edition, English translation 1994

Conceived by the Power of the Holy Spirit. . .

484 The Annunciation to Mary inaugurates "the fullness of time," (Gal 4:4) the time of the fulfillment of God’s promises and preparations. Mary was invited to conceive him in whom the "whole fullness of deity" would dwell "bodily." (Col 2:9) The divine response to her question, "How can this be, since I know not man?" was given by the power of the Spirit: "the Holy Spirit will come upon you." (Lk 1:34-35)

485 The mission of the Holy Spirit is always conjoined and ordered to that of the Son. (Cf. Jn 16:14-15) The Holy Spirit, "the Lord, the giver of Life," is sent to sanctify the womb of the Virgin Mary and divinely fecundate it, causing her to conceive the eternal Son of the Father in a humanity drawn from her own.

486 The Father’s only Son, conceived as man in the womb of the Virgin Mary, is "Christ," that is to say, anointed by the Holy Spirt, from the beginning of his human existence, though the manifestation of this fact takes place only progressively: to the shepherds, to the magi, to John the Baptist, to the disciples. (Cf. Mt 1:20; 2:1-12; Lk 1:35; 2:8-20; Jn 1:31-34; 2:11) Thus the whole life of Jesus Christ will make manifest "how God anointed Jesus of Nazareth with the Holy Spirit and with power." (Acts 10:38)