Gen

Gen 15:4-6

Then GOD's Message came: "Don't worry, he won't be your heir; a son from your body will be your heir."

5 Then he took him outside and said, "Look at the sky. Count the stars. Can you do it? Count your descendants! You're going to have a big family, Abram!"

6 And he believed! Believed GOD! God declared him "Set-Right-with-God."   

He believed God and God declared him "Set-Right-with-God."   It wasn’t anything that he did for God, rather it was what God did for him!  This is what being a child of Abraham means!