General Audience, 17 September 1997 — Vatican.va English text (L'Osservatore Romano English edition) (official text, quoted at the cited paragraph)
On Calvary, Mary united herself to the sacrifice of her Son and made her own maternal contribution to the work of salvation, which took the form of labour pains, the birth of the new humanity.
In addressing the words "Woman, behold your son" to Mary, the Crucified One proclaims her motherhood not only in relation to the Apostle John but also to every disciple. The Evangelist himself, by saying that Jesus had to die "to gather into one the children of God who are scattered abroad" (Jn 11:52), indicates the Church’s birth as the fruit of the redemptive sacrifice with which Mary is maternally associated.
This text is under copyright; the cited paragraph is quoted for study, with a link to the full document. Translation: Vatican.va English text (L'Osservatore Romano English edition).
In Jewish Roots of Mary
Why it is cited
'On Calvary, Mary united herself to the sacrifice of her Son and made her own maternal contribution to the work of salvation, which took the form of labour pains, the birth of the new humanity.' The Church born of Mary's birth pangs.
Notes
Two paragraphs from n. 3 of the catechesis; the key sentence is verbatim (British spelling "labour"). The audience does not cite Revelation 12 explicitly.