Genesis 15:16

16 It will be four generations before your descendants come back here, because I will not drive out the Amorites until they become so wicked that they must be punished."

Genesis 15:16 In-Context

14 But I will punish the nation that enslaves them, and when they leave that foreign land, they will take great wealth with them.
15 You yourself will live to a ripe old age, die in peace, and be buried.
16 It will be four generations before your descendants come back here, because I will not drive out the Amorites until they become so wicked that they must be punished."
17 When the sun had set and it was dark, a smoking fire pot and a flaming torch suddenly appeared and passed between the pieces of the animals.
18 Then and there the Lord made a covenant with Abram. He said, "I promise to give your descendants all this land from the border of Egypt to the Euphrates River,
Scripture taken from the Good News Translation - Second Edition, Copyright 1992 by American Bible Society. Used by Permission.