Genesis 15:9-13

9And the LORD said to him, “Bring Me a heifer, a goat, and a ram, each three years old, along with a turtledove and a young pigeon.”

10So Abram brought all these to Him, split each of them down the middle, and laid the halves opposite each other. The birds, however, he did not cut in half. 11And the birds of prey descended on the carcasses, but Abram drove them away. 12As the sun was setting, Abram fell into a deep sleep, and suddenly great terror and darkness overwhelmed him.

13Then the LORD said to Abram, “Know for certain that your descendants will be strangers in a land that is not their own, and they will be enslaved and mistreated four hundred years.