Genesis 15:15-18

As for you, you shall go to your fathers in peace; you will be buried at a good old age. Then in the fourth generation they will return here, for the iniquity of the Amorite is not yet complete.” It came about when the sun had set, that it was very dark, and behold, there appeared a smoking oven and a flaming torch which passed between these pieces. On that day the LORD made a covenant with Abram, saying, “To your descendants I have given this land, From the river of Egypt as far as the great river, the river Euphrates