2 Sam 7:12-13, Isa 55:3-4, Acts 13:34,38
In the Old Testament, God promised to send Christ, the eternal covenant, to King David. (2 Samuel 23:5, 2 Samuel 7:12-13, Isa 55:3-4)
2 Samuel 23:5 Although my house be not so with God; yet he hath made with me an everlasting covenant, ordered in all things, and sure: for this is all my salvation, and all my desire, although he make it not to grow.
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.
Isa 55:3 Incline your ear, and come unto me: hear, and your soul shall live; and I will make an everlasting covenant with you, even the sure mercies of David. 4 Behold, I have given him for a witness to the people, a leader and commander to the people.
Jesus is the Christ God promised to King David in the Old Testament. (Acts 13:34-38)
Acts 13:34 And as concerning that he raised him up from the dead, now no more to return to corruption, he said on this wise, I will give you the sure mercies of David. 35 Wherefore he saith also in another psalm, Thou shalt not suffer thine Holy One to see corruption. 36 For David, after he had served his own generation by the will of God, fell on sleep, and was laid unto his fathers, and saw corruption: 37 But he, whom God raised again, saw no corruption. 38 Be it known unto you therefore, men and brethren, that through this man is preached unto you the forgiveness of sins: