Or to put it another way, in the flood or in the tower of Babel, God was dealing with all people, all creation. When he chooses Abraham, God focuses his love in a different direction. Instead of trying to suppress sin, he chooses one representative of sinful humanity. Then God promises that from this chosen one he will create a new thing: a priesthood. God will create a priestly nation, a people (Israel, eventually) who stand in the gap for all creation. And we know -- because we have skipped ahead and read the rest of the book, and now we read Abraham's story through the filter of Jesus -- that eventually Israel will lead to the Messiah, Jesus, God-with-us, who will not only plead with God for all creation but will give his life as a sacrifice to redeem creation.
It starts with Abraham and Sarah (actually their names are Abram and Sarai when we first meet them) and their nephew Lot, the son of Abram's dead brother Haran.
God speaks to Abram. "Go from your country and your kindred and your father's house to the land that I will show you. I will make of you a great nation, and I will bless you, and I will make your name great, so that you will be a blessing. I will bless those who bless you, and the one who curses you I will curse; and in you all the families of the earth shall be blessed." Here is God's plan, or at least the beginnings of his plan. Abram will become a great nation, a blessing, an opportunity for the world to be blessed.
Genesis 12:4 is one of the most amazing verses in the Bible. "So Abram went ..." John Ortberg has said that "obedience is the means by which we experience (not earn) grace." Abram is not chosen because he obeys God; rather, he is blessed because he believes God has chosen him and acts in obedience to God's choice.
What small step is God calling you to obey today? We often agonize about the big choices, wishing God would make himself clear in the major league decisions. Yet we ignore, we overlook the tiny areas where God's will is so clear. Over the years I've learned that when I am obedient in small things, it opens the way for God to guide me in larger matters. Are you willing to be obedient in small things today?