Genesis 15:4-8

And, behold, the word of the LORD came unto him, saying, This shall not be thine heir; but he that shall come forth out of thine own bowels shall be thine heir.

And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be.

And he believed in the LORD; and he counted it to him for righteousness.

And he said unto him, I am the LORD that brought thee out of Ur of the Chaldees, to give thee this land to inherit it.

And he said, Lord GOD, whereby shall I know that I shall inherit it?