Lk 1:31-33, Acts 2:29-32, Acts 13:22-23
In the Old Testament, God spoke of the coming of Christ, the eternal King, as a descendant of David. (2 Samuel 7:12-13)
2 Samuel 7:12 And when thy days be fulfilled, and thou shalt sleep with thy fathers, I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom. 13 He shall build an house for my name, and I will stablish the throne of his kingdom for ever.
As the Old Testament prophesied, Christ, the eternal King, came as a descendant of David. That Christ is Jesus. (Luke 1:31-33, Acts 2:29-32, Acts 13:22-23)
Luke 1:31 And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name Jesus. 32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
Acts 2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day. 30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne; 31 He seeing this before spake of the resurrection of Christ, that his soul was not left in hell, neither his flesh did see corruption. 32 This Jesus hath God raised up, whereof we all are witnesses.
Acts 13:22 And when he had removed him, he raised up unto them David to be their king; to whom also he gave their testimony, and said, I have found David the son of Jesse, a man after mine own heart, which shall fulfil all my will. 23 Of this man's seed hath God according to his promise raised unto Israel a Saviour, Jesus: