Genesis 15:12-16

When the sun went down, Abram fell sound asleep, and great terror overwhelmed him. Then the LORD said to Abram, “Know for certain that your descendants will be strangers in a foreign country. They will be enslaved and oppressed for four hundred years. But I will execute judgment on the nation that they will serve. Afterward they will come out with many possessions. But as for you, you will go to your ancestors in peace and be buried at a good old age. In the fourth generation your descendants will return here, for the sin of the Amorites has not yet reached its limit.”