Genesis 15:4-6
4 Then behold, the word of Yahweh came to him, saying, “This one will not be your heir; abut one who will come forth from your own body, he shall be your heir.” 5 And He brought him outside and said, “Now look toward the heavens, and anumber the stars, if you are able to number them.” And He said to him, “bSo shall your seed be.” 6 aThen he believed in Yahweh; and He counted it to him as righteousness.