Mary's fiat and Joseph's fiat are the fulfillment of the original harmony between Adam and Eve, the perfect resumption of the Covenant at Sinai.
This Covenant was addressed to both men and women, as Jewish tradition emphasizes: "The Father of the universe proclaimed the ten words and oracles... as the nation, men and women together, had gathered in assembly."(1)
At the beginning of the New Covenant, a man and a woman are called upon, and we have an announcement to Mary (Lk 1:26-38) and another to Joseph (Mt 1:18-25). Following her dialogue with the angel, Mary gives her assent. At first, Joseph thinks of separating his destiny from Mary's, until an angel reveals to him the mission God has for him.
On August 15 1988, Saint John Paul II wrote of Mary: "The new and definitive Covenant of God with humanity begins with a woman, the "woman" of the Annunciation at Nazareth." (2)
The same pope also wrote this about Joseph, one year later, on August 15, 1989: "This just man [Joseph], who bore within himself the entire heritage of the Old Covenant, was also brought into the ‘beginning’ of the New and Eternal Covenant in Jesus Christ." (3)
Thanks, therefore, to the "yes" of a woman (Mary) and the "yes" of a man (Joseph), God brings about the New Covenant: the Son of the Most High, the divine Word takes on our flesh to become, in the most sublime way, Emmanuel - God with us - , and to be designated as “the son of Mary” (Mk 6:3) or “the son of Joseph” (Jn 1:45).
The covenant made on Mount Sinai represented the birth of Israel as God's own people. At Sinai, God created Israel to establish a covenant of love. But just as the disobedience of Adam and Eve, Israel committed the sin of the golden calf and the previously harmonious relationship fell apart (Gen. 3).
Joseph and Mary were faithful to the Covenant. On the basis of their union with God, Joseph and Mary truly lived as one (Gen 2:24).
Adapted and translated from :
A.Serra, Myriam, fille de Sion, Médiaspaul, Paris, 1999 (excerpt)
(1) Philo of Alexandria, De decalogo, 32
(2) John Paul II, Apostolic Letter Mulieris dignitatem (August 15, 1988), § 11
(3) John Paul II, Apostolic Exhortation Redemptoris Custos (August 15, 1989), § 32