23 If John's description of the event at Cana presents Mary's caring motherhood at the beginning of Christ's messianic activity, another passage from the same Gospel confirms this motherhood in the salvific economy of grace at its crowning moment, namely when Christ's sacrifice on the Cross, his Paschal Mystery, is accomplished. John's description is concise: "Standing by the cross of Jesus were his mother, and his mother's sister, Mary the wife of Clopas, and Mary Magdalene. When Jesus saw his mother, and the disciple whom he loved standing near, he said to his mother: 'Woman, behold your son!' Then he said to the disciple, 'Behold, your mother!' And from that hour the disciple took her to his own home" (Jn. 19:25-27). Undoubtedly, we find here an expression of the Son's particular solicitude for his Mother, whom he is leaving in such great sorrow. And yet the "testament of Christ's Cross" says more. Jesus highlights a new relationship between Mother and Son, the whole truth and reality of which he solemnly confirms. One can say that if Mary's motherhood of the human race had already been outlined, now it is clearly stated and established. It emerges from the definitive accomplishment of the Redeemer's Paschal Mystery. The Mother of Christ, who stands at the very center of this mystery-a mystery which embraces each individual and all humanity-is given as mother to every single individual and all mankind. The man at the foot of the Cross is John, "the disciple whom he loved." But it is not he alone. Following tradition, the Council does not hesitate to call Mary "the Mother of Christ and mother of mankind": since she "belongs to the offspring of Adam she is one with all human beings.... Indeed she is 'clearly the mother of the members of Christ...since she cooperated out of love so that there might be born in the Church the faithful.'" And so this "new motherhood of Mary," generated by faith, is the fruit of the "new" love which came to definitive maturity in her at the foot of the Cross, through her sharing in the redemptive love of her Son.
Source: Redemptoris Mater (Vatican.va)