Mary believed in the fulfillment of what had been said to her by the Lord. As Virgin, she believed that she would conceive and bear a son: the "Holy One," who bears the name of "Son of God," the name "Jesus" (= God who saves). As handmaid of the Lord, she remained in perfect fidelity to the person and mission of this Son. As Mother, "believing and obeying...she brought forth on earth the Father's Son. This she did, knowing not man but overshadowed by the Holy Spirit."
For these reasons Mary is honored in the Church "with special reverence. Indeed, from most ancient times the Blessed Virgin Mary has been venerated under the title of 'God-bearer.' In all perils and needs, the faithful have fled prayerfully to her protection." This cult is altogether special: it bears in itself and expresses the profound link which exists between the Mother of Christ and the Church. As Virgin and Mother, Mary remains for the Church a "permanent model." It can therefore be said that especially under this aspect, namely as a model, or rather as a "figure," Mary, present in the mystery of Christ, remains constantly present also in the mystery of the Church. For the Church too is "called mother and virgin," and these names have a profound biblical and theological justification.
The Church "becomes herself a mother by accepting God's word with fidelity." Like Mary, who first believed by accepting the word of God revealed to her at the Annunciation and by remaining faithful to that word in all her trials even unto the Cross, so too the Church becomes a mother when, accepting with fidelity the word of God, "by her preaching and by baptism she brings forth to a new and immortal life children who are conceived of the Holy Spirit and born of God." This "maternal" characteristic of the Church was expressed in a particularly vivid way by the Apostle to the Gentiles when he wrote: "My little children, with whom I am again in travail until Christ be formed in you!" (Gal. 4:19) These words of Saint Paul contain an interesting sign of the early Church's awareness of her own motherhood, linked to her apostolic service to mankind. This awareness enabled and still enables the Church to see the mystery of her life and mission modelled upon the example of the Mother of the Son, who is "the first-born among many brethren" (Rom. 8:29).
Excerpts from Redemptoris Mater by His Holiness Pope John Paul II (see and click link)
It can be said that from Mary the Church also learns her own motherhood: she recognizes the maternal dimension of her vocation, which is essentially bound to her sacramental nature, in "contemplating Mary's mysterious sanctity, imitating her charity and faithfully fulfilling the Father's will." If the Church is the sign and instrument of intimate union with God, she is so by reason of her motherhood, because, receiving life from the Spirit, she "generates" sons and daughters of the human race to a new life in Christ. For, just as Mary is at the service of the mystery of the Incarnation, so the Church is always at the service of the mystery of adoption to sonship through grace.
Excerpts from Redemptoris Mater by His Holiness Pope John Paul II (see and click link)