Chapter ten lists the descendants of Noah’s three sons and explains how the various nations came about. “From these the nations spread out over the earth after the flood.” Not surprisingly, everyone is descended from Noah’s family and therefore spoke the same language. Today’s language variation is explained in chapter 11, which begins with the desire of the people to build a tower for themselves so that they will make a name for themselves and not be scattered over the face of the whole earth. Of course in reverse fashion their action leads to their name being lost and the people being scattered to the four corners of the world without a common language. The remainder of chapter 11 traces the descent to Abram. It quickly passes over hundreds of years of history before slowing down and widening out to explain Abram and his brothers. This explains where Abram came from and his relationship to Lot who will become important as well.
In Genesis 12, God makes an offer to Abram that he can hardly refuse: “I will make you into a great nation, and I will bless you; I will make your name great, and you will be a blessing. I will bless those who bless you, and whoever curses you I will curse; and all peoples on earth will be blessed through you” (12:2-3). The end of this is quoted in Galatians 3:8 where Paul explains how this promise was fulfilled in blessing all the peoples on earth. Obviously Abram had to have faith to believe a crazy promise like this. He was just some average guy and God is promising all of this to him! First he will have to learn to rely on God rather than his own cunning as events in Egypt soon demonstrate.