Why Abraham, yes, why Abraham? This puzzled me too, especially when this started out to be about the fullness of the Gentiles. One thing we know for a fact is that God chose him. We also have seen the many men and women that God did choose to fulfill His plan. We are just his instruments, and in Jeremiah 29, He tells us that He has a plan for us all and it is all for our good. When we chose someone, it makes them very special. Two things come to mind: one is that Jesus chose us, the other is the adoptive parents, selecting that very little precious someone to be there's and to take care of and provide for him/her. I know that from experience and have been so very blessed because of that. What a joy and blessing. Everyone that God has chosen--Adam to be the first man, Noah to start the whole new race because of his faith, Abraham to be the father of many nations (could Noah have had anything to do with this?), Sarah had a closed womb (she was not the only woman in the Bible that had a closed womb and God opened it for His purpose)--shows us something else: all in God's time. Noah was chosen at the right time, Abraham was chosen at the right time, Isaac was born at the right time (it sure wasn't Abraham and Sarah's time), also Mary and Joseph were chosen, because God had a major plan for them. This story also shows us something about faith. All these mentioned above were chosen because of their faith, and yes, they were not perfect and neither are we. But there isn't any bad or evil thing that God can't turn around and bring out the best in it. I think our brother Saul/Paul is a great example of that.