Verse 16 alerts us to the fact that, though Joseph was Mary's husband, Jesus was born of Mary only.
We know from the Gospel of Luke that after Mary stayed with Elizabeth for about three months she returned to Nazareth. Several months had passed since the time of the Annunciation. She alone knew that she was with child, that is of people living in Nazareth. She was engaged to Joseph before she conceived. Luke 1:27.
How did Joseph discover that Mary was with child? There are several possibilities:
But we don't know.
The verse links this account to the genealogy and points back to verse 16.
"Birth" means "origin, birth." In this accounts it includes the explanation of the conception and birth of Jesus.
Note that Mary is called His mother, for obvious reasons.
"Married" denotes marriage as opposed to engagement, not sexual intercourse.
"She was found" is a good translation. TEV and NEB read "she was found out" which implies that Joseph discovered it. That is an interpretation, not a translation.
This verse and the latter part of verse 20 clearly state the cause and origin of Jesus' conception.
"Righteous man" is applied to Joseph. And though the word is not applied to Mary, she was plainly a believer. Zacharias, Elizabeth and Simeon were "righteous," justified by faith. It denotes their relationship to God. In other words, Joseph was a child of God. Only the NIV reads: "a righteous man." KJV, NKJV and RSV read "a just man." Justus is Latin for the Greek word used here. AAT is poor: "A good man." It's more than that. The other translations are not recommended. LB: "A man of stern principle." TEV: "A man who always did what was right." JB: "Being a man of honor." NEB: "Being a man of principle." The Greek word "righteous" denotes a relationship with God.
Out of Joseph's righteousness flows his sanctification. He did not want to hurt Mary. He did not want the public to consider Mary as an adulteress.
"He had in mind." He came to a decision. He wanted to do this quietly, without a public trial, without even a record of the reason for the divorcement. Even before the angel appeared to Joseph, his attitude and decisions were guided and caused by the Lord Himself. This is not to be overlooked. The only point we are making is that Joseph was not cruel.
He had already resolved to divorce Mary but was giving it some further thought. Even after a decision, an important decision, has been made, a wise man thinks it over again before acting. We think that is the point.
While Joseph was in great sorrow and contemplation, behold, "of all things." In the hour of great need and sorrow, the Lord intervenes to cause us to do the right thing and to banish our sorrow. This angel was probably Gabriel, who had already appeared to Mary, Luke 1:26.
Acts 2:17 may be a parallel but we do not believe, with Lenski, that it is the fulfillment of Matthew 1:19. It speaks of a different subject. This was no ordinary dream, because the angel actually appeared. It reminds us of Hebrews 1:14.
"Son of David" occurs often in the New Testament to refer to Jesus. But the sole exception is this one addressed to Joseph. It denotes high honor. Note how often the Scriptures say to God's children: "Fear not" which implies that they are fearful.
"Take Mary home" means "take to yourself." Mary already was his wife because of the betrothal. Because of Deuteronomy 22:23-24 some maintain that the pledge of betrothal was binding before God as wedlock itself. Others consider betrothal only a Jewish custom. At any rate she is already considered Joseph's wife.
The angel tells Joseph why he should not be afraid. Scripture never says "Fear not" without giving the reason why.
"Conceived" or "generated." Life begins at conception. In this case the Holy Spirit gives life.
The angel continues. The male sex of Jesus is foretold.
Thus far Joseph has been told to do two things:
By the way, no prophecy in the Old Testament gave Jesus this name, the name by which He is most commonly known. But it was prophesied very shortly before His birth, only to His parents. See Luke 1:31.
Then follows another explanation, giving the reason for the name. "He will" is "He Himself" and excludes all other possibilities. "Save" means to rescue and bring to safety. It covers His entire Soteriological work.
"His people" includes the Covenant people but also includes the Gentiles by extension.
"From their sins" eliminates any and all ideas of Jesus as a political Savior. "Their" sins shows that the people are the cause and they are responsible. Jesus came to save and separate people from the guilt and power of sin. How simple and how important! There's just no Christmas without forgiveness of sins.
This might be a paragraph break, noting that the Evangelist is giving an explanation. It might be a continuation of the message of the angel. We have no opinion on this matter.
Note that God is the primary speaker, the prophet is the agent.
In Isaiah 7:14 this prophecy is called a sign, a clear proof of the help and deliverance of the Lord. In Isaiah 7:14 both the Hebrew and the LXX have the article before "virgin" as does Matthew 1:23. Only KJV and RSV have "a virgin." All other translations have the definite article, and rightly so. There was only ONE virgin who conceived and gave birth. For this reason alone this must be called a rectilinear prophecy, not a typical prophecy.
Both the Hebrew and the LXX have "thou shalt call" as in verse 21 here. The prophecy refers either to Joseph of Mary with "thou." Here we have "they," both Mary and Joseph and millions since that time.
Bengel: There are many particulars, in which Matthew observes that the event announced by the angel corresponded exactly with the prediction of Isaiah: 1) A virgin pregnant and becoming a mother; 2) A male child; 3) The nomenclature of the child; 4) The interpretation of the name.
The last clause in verse 23 could not have been spoken by the angel. It was written by the Evangelist who translated the Hebrew into Greek for his readers: "With us God."
Bengel: It signifies the God-man. For the union of the divine and human natures of Christ is the foundation of the union of God with human beings.
Ylvisaker: He who was conceived in Mary by the Holy Ghost and who was born of her is God with us, God one of us, a part of humanity, God in our flesh and blood. There are these two natures in this one person, a truth fraught with the most glorious comfort.
Delitzsch: The incarnation is, indeed, a veiled mystery in the Old Testament, but the veil is not so dense that it admits of no rays striking through . . . this 'virgin' was and remained a riddle in the Old Testament, mightily stirring up the inquiry and search (1 Peter 1:10-12), and awaiting a solution in historic fulfillment.
Lenski: 'Immanuel' was not a given name but was description of the divine nature of Jesus and of His incarnation.
Fahling: Joseph hesitated no more. He understood and believed . . . . This is indeed a characteristic of the silent saint, of whom in all the Scriptures not a word or phrase is recorded. Silently he performed his duty. And the highest duty towards Mary and the unborn Jesus demanded immediate marriage, which would afford not only outward, but also moral protection to both . . . . Thus Joseph showed his faith. The sole purpose of his marriage to Mary was now to legitimize the Child, the Messiah, whose advent was now at hand.
There was one exception in their relationship, until she gave birth. It was a conclusion which Mary and Joseph drew from what Gabriel had told each of them.
Many have followed Luther who called Mary semper virgo, which means "always a virgin." That can't be proved or disproved nor is it an article of faith. On the one hand the verse does not say that they had intimate relations after the birth. On the other hand "he was not knowing her" might indicate that continuous practice after the birth.
Bengel: With regard to the remainder of her married life, the reader is left to form his own opinion.
Fahling: Really it does not matter. The chief consideration is not 'What think you of Mary?' but 'What think you of Christ?'
Lenski: The ordinary reader must take it that Matthew was altogether unconcerned about the intimacy after the birth.
True. It is none of our business. What happens between husband and wife is extremely personal and their business only.
Note: The essence of marriage begins with a promise, not just with a ceremony.