He fulfilled the promise made to Abraham, which God had promised him, to make his seed as the stars of heaven.
For this Christ did, who was born of the Virgin who was of Abraham’s seed, and constituted those who have faith in Him lights in the world, and by the same faith with Abraham justified the Gentiles.
[…] And He fulfilled the promise to David; for to him God had promised that of the fruit of his body He would raise up an eternal King, whose kingdom should have no end.
[…] Thus then He gloriously achieved our redemption, and fulfilled the promise of the fathers, and abolished the old disobedience.
The Son of God became Son of David and Son of Abraham; perfecting and summing up this in Himself, that He might make us to possess life.
The Word of God was made flesh by the dispensation of the Virgin, to abolish death and make man live. For we were imprisoned by sin, being born in sinfulness and living under death.
But God the Father was very merciful: He sent His creative Word, who in coming to deliver us came to the very place and spot in which we had lost life, and brake the bonds of our fetters.
And His light appeared and made the darkness of the prison disappear, and hallowed our birth and destroyed death, loosing those same fetters in which we were enchained.
And He manifested |the resurrection Himself becoming the first-begotten of the dead (Rev. 1:5), and in Himself raising up man that was fallen, lifting him up far above the heaven to the right hand of the glory of the Father: even as God promised by the prophet, saying: And I will raise up the tabernacle of David that is fallen (Amos 9:2); that is, the flesh that was from David.
And this our Lord Jesus Christ truly fulfilled, when He gloriously achieved our redemption, that He might truly raise us up, setting us free unto the Father.
And if any man will not receive His birth from a virgin, how shall he receive His resurrection from the dead? For it is nothing wonderful and astonishing and extraordinary, if one who was not born rose from the dead: nay indeed we cannot speak of a resurrection of him who came unto being without birth.
For one who is unborn and immortal, and has not undergone birth, will also not undergo death. For he who took not the beginning of man, how could he receive his end?
Irenaeus of Lyons (2nd century AD – c. 202): Demonstration of the Apostolic Preaching, 35-38.