CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 962–966

962 "We believe in the communion of all the faithful of Christ, those who are pilgrims on earth, the dead who are being purified, and the blessed in heaven, all together forming one Church; and we believe that in this communion, the merciful love of God and his saints is always [attentive] to our prayers" (Paul VI, CPG § 30).
963 Since the Virgin Mary's role in the mystery of Christ and the Spirit has been treated, it is fitting now to consider her place in the mystery of the Church. "The Virgin Mary . . . is acknowledged and honored as being truly the Mother of God and of the redeemer. . . . She is 'clearly the mother of the members of Christ' . . . since she has by her charity joined in bringing about the birth of believers in the Church, who are members of its head." "Mary, Mother of Christ, Mother of the Church."
964 Mary's role in the Church is inseparable from her union with Christ and flows directly from it. "This union of the mother with the Son in the work of salvation is made manifest from the time of Christ's virginal conception up to his death"; it is made manifest above all at the hour of his Passion:

Thus the Blessed Virgin advanced in her pilgrimage of faith, and faithfully persevered in her union with her Son unto the cross. There she stood, in keeping with the divine plan, enduring with her only begotten Son the intensity of his suffering, joining herself with his sacrifice in her mother's heart, and lovingly consenting to the immolation of this victim, born of her: to be given, by the same Christ Jesus dying on the cross, as a mother to his disciple, with these words: "Woman, behold your son."

965 After her Son's Ascension, Mary "aided the beginnings of the Church by her prayers." In her association with the apostles and several women, "we also see Mary by her prayers imploring the gift of the Spirit, who had already overshadowed her in the Annunciation."
966 "Finally the Immaculate Virgin, preserved free from all stain of original sin, when the course of her earthly life was finished, was taken up body and soul into heavenly glory, and exalted by the Lord as Queen over all things, so that she might be the more fully conformed to her Son, the Lord of lords and conqueror of sin and death." The Assumption of the Blessed Virgin is a singular participation in her Son's Resurrection and an anticipation of the resurrection of other Christians:

In giving birth you kept your virginity; in your Dormition you did not leave the world, O Mother of God, but were joined to the source of Life. You conceived the living God and, by your prayers, will deliver our souls from death.