Genesis 15:8-11

And he said, O Lord Jehovah, whereby shall I know that I shall inherit it? And he said unto him, Take me a heifer three years old, and a she-goat three years old, and a ram three years old, and a turtle-dove, and a young pigeon. And he took him all these, and divided them in the midst, and laid each half over against the other: but the birds divided he not. And the birds of prey came down upon the carcasses, and Abram drove them away.