Why the Virgin Birth of the Son?

Have you ever wondered why Matthew 1:23 quotes Isaiah 7:14?  Perhaps the ready answer is that the quote substantiates the virgin conception and birth of Christ, which is true enough.  However, the text raises a number of questions.  For instance, why did God promise a virgin conceived and virgin born son in the line of David?

To answer that question we need to travel back in time to the day when Isaiah confronted King Ahaz on the highway to Fuller's Field (Isa 7).  On that day, King Ahaz was in trouble.  He had not only refused to join forces with Damascus and Israel against the rising power of Assyria, it was worse, he had sought an alliance with Assyria!  Now, Damascus and Israel were coming to teach him a lesson.  But Isaiah the prophet met King Ahaz to tell him that there was another way.  He did not have to side with Damascus and Israel nor did he have to side with Assyria. He was the Son of David.  He was in the line and lineage of the man after God's own heart.  God would protect him and preserve him from all three!  What is more, God would give him a sign confirming His word.  God invited him to ask for a sign in the highest heavens or the depths of Sheol; ask anything!  But he didn't.  Ahaz claimed piety for his reason; he would not tempt God.  But the raison d'être was a bit different.

Second Kings 16:7 records the awful truth.  Here is the text.  “So Ahaz sent messengers to Tiglath-Peleser king of Assyria, saying, ‘I am your servant and your son; come up and deliver me from the hand of the king of Aram and from the hand of the king of Israel, who are rising up against me!”  Did you see that?  The Son of David postured himself as the son of Tiglath Pileser, king of Assyria!  Ahaz needed no sign from his heavenly Father because he had forsaken the family of God!  He was petitioning for adoption in the family of Assyria.

Now, if we fast forward to Matthew’s gospel we learn several important lessons.  First, David is the focal point of the opening genealogy. It is his line under consideration. The David theme continues in 1:20 when we are told that Joseph, Jesus’ adopted father, is a son of David. And when the angel appears to Joseph and instructs him to name Mary’s Spirit conceived son we are to understand that this naming is part and parcel of adoption. According to one scholar, Joseph david-ed Jesus. He adopted him.  In fact, inspired Matthew goes to great pains to demonstrate this adoption. In Matthew 1:18-25 we find almost two identical sentences regarding the naming of Jesus.  The first is in verse 21 and the second is in verse 25.

Verse 21, καὶ καλέσεις τὸ ὄνομα αὐτοῦ Ἰησοῦν

                And you shall call his name Jesus             

Verse 25, καὶ ἐκάλεσεν τὸ ὄνομα αὐτοῦ Ἰησοῦν.

                 And he called his name Jesus

It is clear that we are to understand that Jesus is Joseph’s son, a son of David by adoption. However, it’s the verse situated between these verses that clarifies Jesus’ identity. Not only is he the adopted son of a son of David, he is God the Son.  Again, notice the similarity in the verses.

Verse 21, καὶ καλέσεις τὸ ὄνομα αὐτοῦ Ἰησοῦν

                  You shall call his name Jesus

Verse 23, καὶ καλέσουσιν τὸ ὄνομα αὐτοῦ Ἐμμανουήλ

                  And they shall call his name Immanuel

Verse 25, καὶ ἐκάλεσεν τὸ ὄνομα αὐτοῦ Ἰησοῦν.

                 And he called his name Jesus

Now, what are we to make of this?  How does it help to answer the question we posed earlier?  Why did God promise that a virgin conceived and virgin born son would be born in the line of David? The answer is now apparent.  Jesus, God the Son, born of a virgin, was sent to be adopted into the line of David in order to be the faithful son of David who alone could sit on the throne of David because he alone would be faithful to his heavenly Father. He is Christ the Lord!   

Jeffrey A. Stivason is the pastor of Grace Reformed Presbyterian Church in Gibsonia, PA. He also holds a Ph.D. in systematic theology from Westminster Theological Seminary in Philadelphia, PA.  Jeff is the author of From Inscrutability to Concursus (P&R), he has contributed to The Jonathan Edwards Encyclopedia (Eerdmans) and is the Executive Editor for Place for Truth.