Genesis 15:9-12
15:9 The Lord said to him, “Take for me a heifer, a goat, and a ram, each three years old, along with a dove and a young pigeon.”
15:10 So Abram took all these for him and then cut them in two and placed each half opposite the other, but he did not cut the birds in half.
15:11 When birds of prey came down on the carcasses, Abram drove them away.
15:12 When the sun went down, Abram fell sound asleep, and great terror overwhelmed him.