Genesis 15:15-18

You, however, will go to your ancestors in peace and be buried at a good old age. In the fourth generation your descendants will come back here, for the sin of the Amorites has not yet reached its full measure.” When the sun had set and darkness had fallen, a smoking firepot with a blazing torch appeared and passed between the pieces. On that day the LORD made a covenant with Abram and said, “To your descendants I give this land, from the Wadi of Egypt to the great river, the Euphrates