Jesus is both the creator and descendant of David

Isaiah 11:1--A shoot will come up from the stump of Jesse; from his roots a Branch will bear fruit.

Matthew 1:2-26--See this text for the lineage of Abraham to David, and David to Jesus.

Matthew 22:41-46--While the Pharisees were gathered together, Jesus asked them, 42"What do you think about the Christ? Whose son is he?"  42  "The son of David," they replied.  43 He said to them, "How is it then that David, speaking by the Spirit, calls him `Lord'? For he says, 44"`The Lord said to my Lord: "Sit at my right hand until I put your enemies under your feet." ' 45If then David calls him `Lord,' how can he be his son?" 46No one could say a word in reply, and from that day on no one dared to ask him any more questions.

Romans 1:3 -- ...regarding his Son, who as to his human nature was a descendant of David....

Revelation 5:5
Then one of the elders said to me, "Do not weep! See, the Lion of the tribe of Judah, theRoot of David, has triumphed. He is able to open the scroll and its seven seals."

Revelation 22:16 -- "I, Jesus, have sent my angel to give you this testimony for the churches. I am the Root and the Offspring of David, and the bright Morning Star."

Comment:

When Jesus declares he is the "Root and Offspring of David," he is exposing two facts:   1) David is descended from Jesus and 2)  Jesus is descended from David. How can this be? Jesus, the human, did not exist actually before David, but the spirit of God did. The "Root" is the Spirit of God. The Spirit that spoke the worlds into existence out of nothing.   The same Spirit that selected David as king and then blessed his kingdom.  It was that Spirit which overshadowed Mary to become the father of Jesus.  The Spirit of God then took on the identity of Jesus, by living in him. Jesus' human ancestry is traced back to David and Abraham.  His bloodline comes directly from God.  Jesus is the Spirit of God from the Old Testament who became a man in the New Testament, thereby the "Root and Offspring of David."