Genesis 15:5-7

He took him outside and said, “Look up at the sky and count the stars—if indeed you can count them.” Then he said to him, “So shall your offspring be.” Abram believed the LORD, and he credited it to him as righteousness. He also said to him, “I am the LORD, who brought you out of Ur of the Chaldeans to give you this land to take possession of it.”