Genesis 15:5-7

And He took him outside and said, “Now look toward the heavens, and count the stars, if you are able to count them.” And He said to him, “So shall your descendants be.” Then he believed in the LORD; and He reckoned it to him as righteousness. And He said to him, “I am the LORD who brought you out of Ur of the Chaldeans, to give you this land to possess it.”