Right at the beginning of the passage God declares to Abraham that he is Almighty. God is Almighty! He can do whatever he wants to do, without any limitations. That's the first thing he says to Abraham because he's ready to fulfill his promise with Abraham and Sarah that they will have a son. The fact that they were so old made this promise seem much more impossible. But with God nothing is impossible. They had to wait till they were very very old but even their age was not strong enough to keep God from doing this Mighty thing. So I have to ask myself, what does God want to do in and through my life? Am I walking Faithfully with God? What do I believe he can do in and through my life?