Youcat commented through CCC - Question n. 85 - Part II.

YOUCAT Question n. 85 - Part II. Why is Mary our mother also?

(Youcat answer - repeated) Mary is our mother because Christ the Lord gave her to us as a mother.  

A deepening through CCC

(CCC 965) After her Son's Ascension, Mary "aided the beginnings of the Church by her prayers" (LG 69). 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" (LG 59).   

Reflecting and meditating 

(Youcat comment) “Woman, behold, your son!... Behold, your mother!” (Jn 19:26b-27a). The second command, which Jesus spoke from the Cross to John, has always been understood by the Church as an act of entrusting the whole Church to Mary. Thus Mary is our mother, too. We may call upon her and ask her to intercede with God.    

(CCC Comment)

(CCC 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" (LG 59; cf. Pius XII, Munificentissimus Deus (1950): DS 3903; cf. Rev 19:16). 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 (Byzantine Liturgy, Troparion, Feast of the Dormition, August 15th).    

(This question: Why is Mary our mother also? is continued)