From an allocution by Pope Saint Paul VI at the Second Vatican Council
Meditating on the close relationships between Mary and the Church, for the glory of the Virgin Mary and for our own consolation, we proclaim the Most Blessed Mary Mother of the Church, that is to say of all the people of God, of the faithful as well as of the pastors, who call her the most loving Mother. And we wish that the Mother of God should be still more honoured and invoked by the entire Christian people by this most sweet title.
This is a title, venerable brothers, not new to Christian piety; it is precisely by this title, in preference to all others, that the faithful and the Church address Mary. It truly is part of the genuine substance of devotion to Mary, finding its justification in the very dignity of the Mother of the word Incarnate.
Just as, in fact, the divine maternity is the basis for her special relationship with Christ, and for her presence in the economy of salvation brought about by Jesus Christ, thus it also constitutes the principal basis for the relations between Mary and the Church, since she is the mother of him who, right from the time of his Incarnation in her virginal bosom, joined to himself as head his Mystical Body which is the Church. Mary, then, as mother of Christ, is mother also of all the faithful and of all the pastors.
It is therefore with a soul full of trust and filial love that we raise our glance to her, despite our unworthiness and weakness. She, who has given us in Jesus the fountainhead of grace, will not fail to succour the Church, now flourishing through the abundance of the gifts of the Holy Ghost and setting herself with new zeal to the fulfilment of its mission of salvation.
And our trust is even more lively and fully corroborated if we consider the very close links between this heavenly Mother of ours and mankind. Although adorned by God with the riches of admirable prerogatives, to make her a worthy Mother of the Word Incarnate, she is nevertheless very close to us. Daughter of Adam, like ourselves, and therefore our sister through ties of nature, she is, however, the creature who was preserved from original sin in view of the merits of the Saviour, and who possesses besides the privileges obtained the personal virtue of a total and exemplary faith, thus deserving the evangelical praise, beata quae credidisti (blessed art thou who believed). In her earthly life, she realised the perfect image of the disciple of Christ, reflected every virtue, and incarnated the evangelical beatitudes proclaimed by Christ. Therefore in her, the entire Church, in its incomparable variety of life and of work, attains the most authentic form of the perfect imitation of Christ.