Genesis 15:6-10

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?

And he said unto him, Take me an heifer of three years old, and a she goat of three years old, and a ram of three years old, and a turtledove, and a young pigeon.

And he took unto him all these, and divided them in the midst, and laid each piece one against another: but the birds divided he not.