Betrothed Guardians of a Sacred Mystery

I was contemplating something while re-reading St. Thomas Aquinas' summa conversations on the Virgin Mary's betrothal to Joseph. (STh, Third Part, 29, 1)

Mary's cousin Elizabeth gives an inspired witness to the manner of Mary's conception. (cf. Luke 1:39-45) On the other hand, the Virgin Mary does not defend the manner of her pregnancy to Joseph; who only observes that she is pregnant.

The reality is that she left the whole matter to the wisdom of the LORD God, who sent an angel to Joseph to explain the manner (who, what, when, how, where, why) of Mary's pregnancy:

Joseph, son of David, do not be afraid to receive alongside (Greek | paralambanó) Mary as your wife, for conceived in her is of the Holy Spirit. (Matthew 1:20)

Joseph as betrothed husband and guardian makes it possible for the Virgin Mary not to explain (or need to explain) the mystery of the conception and birth of the Child to anyone. She is freed from defending her dignity and the dignity of her Son's conception and birth.

In fact, neither Mary or Joseph are compelled to explain the mystery of Jesus Christ's conception and birth.

Is this not Jesus, the son of Joseph, whose father and mother we know? How then can He say, ‘I have come down from heaven?’ (cf. John 6:42; Matthew 13:55-56; Luke 4:22)

It also seems that Mary and Joseph did not discuss such things in detail to the child Jesus Christ:

When His parents saw Him, they were astonished. 'Child, why have You done this to us?' His mother asked. 'Your father and I have been anxiously searching for You.'” Jesus asked, “Why were you looking for Me? Did you not know that I had to be in My Father’s house?” But they did not understand the statement He was making to them. Then He went down to Nazareth with them and was obedient to them. But His mother treasured up all these things in her heart. (Luke 2: 48-51)

It is my impression that their "not understanding" is due to a sudden and profound awareness: "He knows." In other words, they know that He knows.

When such an intimate conversation -- about the (who, what, when, where, and how) of Incarnation emerges among the disciples of Jesus Christ -- is not certain. Perhaps with the coming of the Holy Spirit on Pentecost the door is opened:

With one accord they all continued in prayer, along with the women and Mary the mother of Jesus, and with His brothers. (Acts 1:14)

The disciples knew on some level that Jesus Christ is the Son of the Father. "But how is He son of Mary?" The Gospel inferences in retrospect are too many.

Matthew's Gospel, so it is said, reflects language rooted in the person of Joseph. It is quite early and obscurely hidden; as if preserving the divine mystery at all costs.

Luke's Gospel, so it is said, reflects language rooted in the person of Mary. It is quite later and not so obscurely hidden; as if manifesting the divine mystery at all costs. (cf. Luke 1: 1-4; 2:19, 51)

It is not known what language is shared between Mary, the mother of Jesus Christ and the beloved disciple. (cf. John 19: 25-27) Perhaps, it would have been too delicate a treasure to share until after the outpouring of the Holy Spirit on Pentecost.