2 Samuel 7:12 establishes one of the most basic requirements of the Messiah: he has to be descended biologically and literally from David. That is the whole basis of the Messianic promise. God said to David:

“I will raise up your seed after you, who will come forth from your own body, and I will establish his kingdom.”

That is biological language. The promised king is to come from David’s own descendants. He has to be younger than David because David is his ancestor, and obviously you cannot be older than your own ancestor.

This is why the birth narratives of Jesus are so important.

If Jesus has to be descended from David, it could not be biologically through Joseph, because Joseph was not his biological father. Joseph was certainly Jesus’ legal father, but the Gospel accounts are equally clear that he was not the man who generated Jesus.

Matthew 1:18 says: “The origin of Jesus Messiah was like this: His mother, Mary, was engaged to be married to Joseph, but before they came together she became pregnant through holy spirit.”

And in Matthew 1:20 the angel explains to Joseph: As he was thinking about these things, an angel of the Lord appeared to him in a dream and said, “Joseph, son of David, do not be afraid to take Mary to be your wife, because the child who has been fathered in her is from holy spirit.”

That wording is enormously important. What is being fathered in Mary is from holy spirit. It is, of course, a conception, but the point is that Jesus did not come into existence through Joseph. God worked a biological miracle in Mary.

God is therefore the Father of Jesus by miracle. Joseph is not his biological father.

So how can Jesus be biologically descended from David? It has to be through his mother.

Mary therefore has to belong to the Davidic line, and Jesus, through Mary, is literally and biologically descended from David. He is not merely legally associated with David. The Messianic promise requires actual descent.

This is precisely what Gabriel tells Mary in Luke 1:32:

“He will be great and will be called Son of the Most High, and the Lord God will give him the throne of his father David.”

Notice the language carefully.

The miraculous baby whom Mary herself is going to bear is called “Son of the Most High,” and the Lord God will give him “the throne of his father David.”

Why call David his father if Jesus has no biological connection with David?

The whole statement assumes that Jesus really belongs to David’s family line.

And Gabriel continues: “He will reign as king over the house of Jacob forever, and his Kingdom will never end.” Luke 1:33

That is the fulfillment of the promise of 2 Samuel 7. The descendant of David is born, and God will eventually give him David’s throne.

Paul says exactly the same thing in Romans 1:3

“Concerning His Son, who came into existence from the seed of David according to the flesh.”

That is extraordinarily clear. Jesus came into existence “from the seed of David according to the flesh.” Paul does not say that Jesus merely inherited a legal claim to David’s throne through Joseph. He says that Jesus came from David’s seed according to the flesh. That is biological descent. And since Matthew tells us that Joseph did not father Jesus, that biological descent must come through Mary.

This is also why the miraculous conception must not be turned into the idea that Jesus somehow existed before his birth and merely passed through Mary. That would destroy the force of the Davidic promise. The Messiah is not someone older than David who later enters David’s family. He is David’s descendant.

He comes from David.

He is David’s seed.

He is born from David’s family line.

And yet, because of the miraculous act of God in Mary, he is uniquely God’s Son.

Luke explains this with remarkable simplicity:

“Holy spirit will come upon you, and power of the Most High will overshadow you. For that reason precisely the one being brought into existence will be called holy, Son of God.” Luke 1:35

“For that reason precisely.” Why is Jesus the Son of God? Because of what happened in Mary.

The Son of God is brought into existence by the miraculous creative action of God in his mother. That is why God is his Father. Joseph is not the biological father of Jesus. God is his Father by miracle, while Mary supplies the genuine human and Davidic descent required of the Messiah.

This gives us a perfectly coherent biblical picture. The Messiah must be the biological descendant of David according to 2 Samuel 7. Jesus is conceived miraculously in Mary, not fathered by Joseph, according to Matthew 1.

Gabriel identifies the child Mary bears as the Son of the Most High who will receive the throne of “his father David,” according to Luke 1. And Paul explicitly says that Jesus came into existence “from the seed of David according to the flesh,” according to Romans 1:3.

So the conclusion is unavoidable.

If Joseph did not biologically father Jesus, but Jesus is nevertheless biologically descended from David, then the Davidic descent has to come through Mary. She must therefore belong to the house and line of David.

Jesus is genuinely the seed of David according to the flesh, genuinely the Son of God by miraculous generation, and genuinely the promised Messiah who will one day sit upon the throne of his father David. That is the beautiful simplicity of the biblical account.