Genesis 15:9-13

9He said to him, "Bring me a heifer three years old, a female goat three years old, a ram three years old, a turtledove, and a young pigeon."

10And he brought him all these, cut them in half, and laid each half over against the other. But he did not cut the birds in half.

11And when birds of prey came down on the carcasses, Abram drove them away.

12As the sun was going down, a deep sleep fell on Abram. And behold, dreadful and great darkness fell upon him.

13Then the Lord said to Abram, "Know for certain that your offspring will be sojourners in a land that is not theirs and will be servants there, and they will be afflicted for four hundred years.