47 At the Council Paul VI solemnly proclaimed that Mary is the Mother of the Church, "that is, Mother of the entire Christian people, both faithful and pastors." Later, in 1968, in the Profession of faith known as the "Credo of the People of God." he restated this truth in an even more forceful way in these words: "We believe that the Most Holy Mother of God, the new Eve, the Mother of the Church, carries on in heaven her maternal role with regard to the members of Christ, cooperating in the birth and development of divine life in the souls of the redeemed." The Council's teaching emphasized that the truth concerning the Blessed Virgin, Mother of Christ, is an effective aid in exploring more deeply the truth concerning the Church. When speaking of the Constitution Lumen Gentium, which had just been approved by the Council, Paul VI said: "Knowledge of the true Catholic doctrine regarding the Blessed Virgin Mary will always be a key to the exact understanding of the mystery of Christ and of the Church." Mary is present in the Church as the Mother of Christ, and at the same time as that Mother whom Christ, in the mystery of the Redemption, gave to humanity in the person of the Apostle John. Thus, in her new motherhood in the Spirit, Mary embraces each and every one in the Church, and embraces each and every one through the Church. In this sense Mary, Mother of the Church, is also the Church's model. Indeed, as Paul VI hopes and asks, the Church must draw "from the Virgin Mother of God the most authentic form of perfect imitation of Christ." Thanks to this special bond linking the Mother of Christ with the Church, there is further clarified the mystery of that "woman" who, from the first chapters of the Book of Genesis until the Book of Revelation, accompanies the revelation of God's salvific plan for humanity. For Mary, present in the Church as the Mother of the Redeemer, takes part, as a mother, in that monumental struggle; against the powers of darkness" which continues throughout human history. And by her ecclesial identification as the "woman clothed with the sun" (Rev. 12:1), it can be said that "in the Most Holy Virgin the Church has already reached that perfection whereby she exists without spot or wrinkle." Hence, as Christians raise their eyes with faith to Mary in the course of their earthly pilgrimage, they "strive to increase in holiness." Mary, the exalted Daughter of Sion, helps all her children, wherever they may be and whatever their condition, to find in Christ the path to the Father's house. Thus, throughout her life, the Church maintains with the Mother of God a link which embraces, in the saving mystery, the past, the present and the future, and venerates her as the spiritual mother of humanity and the advocate of grace.
Source: Redemptoris Mater (Vatican.va)