Following the Tower of Babel account and in the second part of Genesis 11 we come across the lineage of Shem (Noah’s son) to Abram (the patriarch of Israel). Terah was the father of Abram, Nahor and Haran. Haran (the father of Lot) died before his father so Lot became part of Abram’s family, it is suggested that Abram adopted Lot as his own son. Both Abram and Nahor took wives… Abram’s wife was Sarai (his half sister) and Nahor’s wife was Milcah (his niece and Lot’s sister). Sarai could not have children (this is significant later).
Sometime after Nahor died Terah took Abram, Lot and Sarai from Ur of the Chaldeans to go to the land of Canaan but settled in Haran.
Ur – This was the birthplace of Abram and Sarai. The results of archaeological investigations demonstrate that Abraham came from a great city, cultured, sophisticated, and powerful. The landscape was dominated by the ziggurat, or temple tower, and the life of the city was controlled by a religion with a multiplicity of gods. The chief deity was Nannar, or Sin, the moon god, who was also worshiped at Haran.  Upon leaving Ur of the Chaldeans they intended to set out for Canaan but ended up settling in Haran.
Vs 1: The call - Abram was commanded or called by the LORD to leave his country, clan and family and go to a land that God would show him. Abram was called to leave the familiar and go out to the unfamiliar. God calls Abram to do something outrageous. It is outrageous because it would make sense for Abram to stay put in Haran with his elderly father and because his family, possessions and heritage was from this area (Also he was 75 years old). Sometimes God calls individuals to do things that don’t necessarily make a whole lot of sense. It is good to be reminded though that when he does he has a purpose and all the details are taken care of but he may not disclose the plan upfront. It is also good to be reminded that when God calls us to do something that may not make sense, it is always for his sake and his glory and not ours. He is a good God so He will bless what he calls you to do but he doesn’t guarantee it will be an easy and smooth transition.
We see this is true in the case of Jesus’ call to his disciples to leave everything behind and follow him. The Disciples were called to abandoning and trusting Jesus (Come and follow). Every disciple of Jesus gave up something to follow him. In most of their cases it was their livelihood. Some even left their families (they didn’t desert them but took time to follow and walk with Jesus.) In their abandonment they had to put complete trust in Jesus to meet their needs (financially, spiritually and physically) and give them assurance that they were doing God’s will. They had to trust that leaving all behind was for the Kingdom of God.
Vs. 2 – 3: The promise – God will make him into a great nation (this is key since he has no children and his wife is barren). According the NET Bible, “Now God begins to build his covenant people.” It is in this moment God establishes with Abram the blessing of making him a great nation that will bless the world. In contrast to the attitude of those in Babel who wanted to make a name for themselves God declares that HE will make Abram’s name great. He will bless (or make famous) Abram and his family. It is the LORD’s doing and not mans. God’s blessing of Abram will be an example to all nations of the divine blessings of the one and true God. In so doing Abram will be a blessing to the nations. The blessings that others will receive will come from how they treat Abram and his family. God will bless those who bless Abram and he will curse those who dishonor him. God shows favor to Abram. Ultimately in due time the whole world will be blessed because of God’s blessing to Abram.
Why did he choose Abram to be a vessel of blessing to all nations? This is another picture of grace. God chose Abram; because in his sovereignty he was going to accomplish great things. It had nothing to do with Abram. God did not see spectacular characteristics in Abram that made God come to this conclusion and calling. God calls Abram to leave and it may not have been the most sensible thing to do (humanly speaking) but God makes a promise to Abram that he will bless him and his family. Abram certainly couldn’t fully know what that blessing was since he had no children and really no land as of yet. All he had was the promise of God and this was enough for him.
Are God's promises enough for you?
 Elwell, W. A., & Comfort, P. W. (2001). Tyndale Bible dictionary. Tyndale reference library (1281). Wheaton, IL: Tyndale House Publishers.