Most summaries of the story of Abraham and Sarah make them look like models of faith and understanding. A modern hymn in the United Church book claims that for them the call of God was clear. This kind of short-cut version makes them seem so much different from the rest of us who have to feel our way along. But when we look at their whole story, we find that while they trusted God, they had to work out the promise step by step.

Living as nomads in the fertile lands around the Tigris and Euphrates rivers, Abraham and Sarah and their household were used to travel. But in their later years, they hear a call from God to leave this land and travel to a new land. They are promised that they will become a nation and a blessing to all the families of the earth.

Following that promise, they cross the barren dry lands to the west. When they come to the north of what is now Israel, they sense this is the land God promised. They are still nomads, moving up and down the land according to the rains to find pasture.

They were promised a land of plenty, but shortly after they arrive there is a drought and a famine. They have to move on to Egypt for a time.

Up to now, Abraham and Sarah had no children, and it seems that they had adopted a nephew, named Lot, as their heir. But things don't go well, and there is quarrelling between the people who look after their herds. To keep the peace, Lot moves east and Abraham and Sarah go west. As a result, when God comes to him in a vision, Abraham complains that the only heir he has is his steward. "Not to worry," God says. "You will have a son."

Abraham and Sarah talk over this promise. It is a challenge because Sarah has been barren and her monthly cycles have ended. She suggests a surrogate. This is a perfectly acceptable pattern in their day. Her maid-servant is chosen, and this woman bears a son, Ishmael. They celebrate the birth of an heir.

But God comes again. Now another detail of the promise is revealed. God announces that Sarah is included in the promise: "Sarah will have a son," declares the messenger of God. When he hears this, Abraham falls on the ground laughing. When Sarah hears this, she too laughs out loud.

It is important not to miss this moment in the story. These two who we take as models of faith and trust find the details of the promise impossible to believe. They laugh at God's promise. God does not object to their laughter, but simply encourages them to keep going.

And sure enough, nine months later, Sarah bears a son, Isaac.

The two sons might have gotten along fine, but the two mothers do not. There is jealousy between them. They fight. In the end, Ishmael and his mother are sent away. God will not forget him; the older boy will become the father of princes and a great nation. But the family that will be bound to God will come through the younger boy, Sarah's son, Isaac.

Their story does not end with the birth. There is still trouble to work through. Isaac has to grow up. When Sarah dies, Abraham arranges a wife for this son. When Abraham dies, Ishmael and Isaac come together to bury him. And the story continues through Isaac's sons and his grandsons. The promise that took Abraham and Sarah from their home grows.

The thing that the details of the story reveals is that these two faithful people have to feel their way forward. They don't get all the details in the beginning. They have to figure things out as best they can as they go. Which is actually a better model of faithful living. No one gets the whole picture at the start. We have a sense of vision, a pull toward hope, but it has to be worked out step by step as we journey.

Cathy Hird lives near Walters Falls.