Summary
Why is God going to bless Abraham and his family. The last line of God’s promise makes that clear: so that all the families of the earth will find this blessing in you. This is a key component to understanding the rest of the biblical story. This is the key to unlocking the door moving forward:

God’s plan is to rescue and bless his rebellious world through Abraham’s family, and this is why the whole rest of the OT story is just going to focus on the one family; eventually called the people of Israel.

Talking Points
David Russell; Genesis Summary; Abraham Chiasm; Faithfulness Over Knowledge; The Cycle of Humans; Significance of Abraham; Points to Jesus; Where The Story Goes From Here; Where We Go Next!

References
The Book of Genesis, Chapters 1–17 - Victor P. Hamilton
Genesis 1-11 - Samuel Bray & John Hobbins
The Pentateuch as Narrative - John Sailhamer
The Bible Project (Genesis 1-11)
Adam as Israel - Seth Postell