The book of the genealogy of Jesus Christ, the Son of David, the son of Abraham...
See also
Genesis 12:1-3 —
Now the Lord had said to Abram:
Get out of your country, from your family and from your father’s house, to a land that I will show you. I will make you a great nation; I will bless you and make your name great; And you shall be a blessing. I will bless those who bless you, and I will curse him who curses you; And in you all the families of the earth shall be blessed.
Genesis 17:5 —
No longer shall your name be called Abram [“Exalted Father”], but your name shall be Abraham [“Father of a Multitude”]; for I have made you a father of many nations.
Observations
Jesus Christ is the fulfillment of Genesis 12:3
That’s a very long time between God promising and fulfilling
This isn’t the first time God’s given a slow-to-fulfill promise to Abraham — the promise of kids, for example
Things God Does
and other interpretations
God plans way far in the future
God sometimes makes promises for way far in the future
Application
Get used to the idea of waiting patiently for the Lord: He’ll do His thing in the time He likes
But know with complete certainty that He will fulfill His promises, no matter the apparent delay.