Matthew and Luke provide us with information about the conception of Jesus, but when reading Matthew we get the impression that he did not yet know what Luke would learn later. He tells us that Jesus was born not through human intervention but through the power of the Holy Spirit. However, he does not provide us with details about the Mary's converse with the Angel Gabriel, as does the elegant Gospel according to Luke. Matthew consistently shaped his writing to meet the needs of the Jews of his day, by associating the New Testament with the Old. He narrates the bare facts and allows us to ponder them at leisure to absorb the mysteries contained in them. Matthew is much used in the Church Liturgy, perhaps because of his stately language and straightforward and unemotional accounting of the facts that took place.
Now the birth of Jesus Christ took place in this way. When his mother Mary had been betrothed to Joseph, before they came together she was found to be with child of the Holy Spirit; and her husband Joseph, being a just man and unwilling to put her to shame, resolved to divorce her quietly (Mt 1:18-19).
Betrothal was actually a binding marriage contract that was negotiated about at least a year before the husband would take the wife into his house and the marriage would be consummated (see The International Bible Commentary (IBC) 1258), Because the contract made previously before this consummation was binding, it could be terminated only be death or by divorce. Joseph therefore could fully expect that Mary would keep her part of the contract.
When Joseph, probably with great consternation, discovered that Mary was with child, he weighed the circumstances and came up with the inevitable decision: there would have to be a divorce. What else was he to do? Mary had told him nothing, apparently, before she had sped off to her cousin Elizabeth where she remained for three months. When she returned, and after Joseph could see the obvious, a decision had to be made. Matthew says nothing about Joseph discussing the subject with Mary. And she apparently volunteered nothing. Joseph pondered the law. He would cause as little pain to this dear person as the law allowed. But divorce there had to be. He would not accept responsibility for what was to him obviously a rival's child, or someone unknown to him. Then God came to the rescue:
But as he considered this, behold, an angel of the Lord appeared to him in a dream, saying, "Joseph, son of David, do not fear to take Mary your wife, for that which is conceived in her is of the Holy Spirit; she will bear a son, and you shall call his name Jesus, for he will save his people from their sins" (Mt 1:20-21).
With that Joseph learned what Mary already knew, namely that Jesus was conceived miraculously. What a relief it must have been for him to learn that Mary was innocent. But that was the lesser part of the message. The other part he still had to think through: 'You shall call his name Jesus, for he will save his people from their sins." God was imposing on the humble carpenter Joseph a tremendous responsibility. Joseph was to marry the mother of the Messiah! He was being thrust by God onto the stage of the world. It seems that Joseph did not blink, did not hesitate. If this message was from God, as he knew it was, he will rise to the occasion. He will do as the Lord told him to do. Mary, who had remained silent until this time about the Annunciation, likely felt free after this to relate to Joseph the message that she had received from Gabriel. The two were in this together.
The angel's message Joseph that he should take Mary as his wife included implicitly that he should adopt the child as his son. Thereby the child would become a son of David. 'To the ancient world there would be no inconsistency here, for adoption provided one with ancestors as assuredly as did biological descent" (see Harpers Bible Commentary p. 952). This is literally true in many cultures, even today in Japan. Jesus would be legally the Son of Joseph.
Joseph was a man of extraordinary spiritual sensibilities. He immediately sensed that if God had visited Mary, then she was a sacred shrine. She must remain a virgin, and he too. Her body would be for him a closed garden, a sealed fountain. This ardent lifestyle he took upon himself when he consented to the instructions from God given through an angel. The angel told him not to be afraid, and that gave him the assurance that God would protect their marital lives together, to keep it virgin.
That God revealed the mystery to Joseph directly, instead of through Mary, reflects divine respect for Jewish culture, and for human culture in general: Joseph should not learn about his God-given responsibilities through his spouse. Being her husband, the bread-winner of the family, he should be in charge of the family insofar as Jewish culture expected this. Mary already knew that her Son is to be named Jesus. But God was careful to instruct Joseph directly about this. He should not have to learn that from his spouse. This is a delightful side-light on their marital relationship. God, and the angel who had spoken to Joseph, observed cultural niceties with care. Joseph was greatly honored by receiving instructions directly from God who therefore expected him to carry out the orders he had received: to marry and to name his Son Jesus. Very likely Mary did not miss the delicate nuance of God's ways with her and Joseph. She was not to believe that God had commissioned her to be the instructor of Joseph, but both were joined together under the divine providence of God.
Matthew now adds, for the Jews of his day, the prophecy spoken seven hundred years before, now being fulfilled by God coming to live with us:
All this took place to fulfil what the Lord had spoken by the prophet: "Behold, a virgin shall conceive and bear a son, and his name shall be called Emmanuel" (which means, God with us) (Mt 1:22-23).
The term 'maiden" in the Hebrew is translated 'virgin" in the Greek Septuagint. Whether the translation be maiden or virgin, in either case, Mary was that person, the one who now fulfilled the ancient prophesy about a miraculous conception and birth. She would bring the presence of God into Israel by bearing this son, this Emmanuel. This must have astounded Joseph and made him aware of the lofty nature of the vocation to which God was calling him. His son was God now humanly alive in Israel.
This was the fulfillment of the event for which all Israel had been waiting. Joseph likely mulled in his mind: 'If it was an action of God by which Mary conceived, and if her Son is "God with us" then I am called to cooperate in a most holy event. Chrysostom discerns that when the angel told Joseph that the child would save 'His people from their sins,'" Joseph would understand that the Child was divine: "For this is the word of one implying nought else, but that He who is born is God's child, and that the King of those on high is the subject of his discourse. As neither doth forgiving sins belong to any other power. but only to that single essence" (Homily 4,13).
When Joseph awoke from sleep, after God had made this great revelation to him, he probably lost no time in arranging for a meeting with Mary. He had good news for her.
When Joseph woke from sleep, he did as the angel of the Lord commanded him; he took his wife, but knew her not until she had borne a son; and he called his name Jesus (Mt 1:24-25).
But surely Mary must have felt great pain before this. How she yearned to convey the news to Joseph. Did he not have a right to know? The angel had not given instructions about that. Perhaps she prayed as Newman once did: "Lead kindly light, amid the encircling gloom. Lead thou me on. The night is dark and I am weak and lone. Lead thou me on. I ask not now to see the distant shore. One step enough for me."