Genesis 15:12-14

And when the sun was going down, a deep sleep fell upon Abram; and, lo, a horror of great darkness fell upon him. And he said unto Abram, Know of a surety that thy seed shall be sojourners in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years; and also that nation, whom they shall serve, will I judge: and afterward shall they come out with great substance.