Genesis 15:9-12

9So the LORD said to him, “Bring me a heifer, a goat and a ram, each three years old, along with a dove and a young pigeon.” 10Abram brought all these to him, cut them in two and arranged the halves opposite each other; the birds, however, he did not cut in half.

11Then birds of prey came down on the carcasses, but Abram drove them away. 12As the sun was setting, Abram fell into a deep sleep, and a thick and dreadful darkness came over him.