"I will bless you; I will make your name great, and you will be a blessing." — Genesis 12:2
Matthew's record of Jesus' family tree (Matthew 1:1-17) begins with Abraham. Why? Matthew wanted us to remember God's promises to Abraham.
God called Abraham to leave his country and go to the land God would show him. The Lord began to bring his greatest blessing into the world through Abraham and his family. And God made big promises to Abraham: a place to dwell with God, descendants as countless as the stars, and an opportunity to change the world. God would bless Abraham so that through him the entire world would be blessed.
Did Abraham ever see those promises come true? He did have descendants, but not very many by the time he died. The only land he owned at the time of his death was his burial plot. When we see that his descendants continue through 2,000 years of history to include Jesus, however, we finally understand how those promises became fulfilled.
What's more, we, the followers of Christ today, are also spiritual descendants of Abraham (Romans 4:11, 16). And through Jesus, of the line of Abraham, all the people of the world are indeed blessed.
God kept his promises to Abraham. God will keep the promises he makes to us too. Though we don't always see the results in our lifetime, just as Abraham didn't, God is faithful.