John Gills Exposition of the Bible Commentary - Genesis 15:16
And in the fourth generation they shall come hither again ,.... The seed of Abram were in the land of Canaan before their descent into Egypt; and it is here predicted and promised, that they should come thither again, as they did, in the fourth generation of those that descended thither; for Moses and Aaron were the fourth from Levi, or Eleazar from Kohath, and Caleb from Judah; or rather this was in the fourth age or century from the birth of Isaac, when the four hundred were up before... read more
Matthew Henry's Complete Commentary - Genesis 15:12-16
We have here a full and particular discovery made to Abram of God's purposes concerning his seed. Observe, I. The time when God came to him with this discovery: When the sun was going down, or declining, about the time of the evening oblation, 1 Kgs. 18:36; Dan. 9:21. Early in the morning, before day, while the stars were yet to be seen, God had given him orders concerning the sacrifices (Gen. 15:5), and we may suppose it was, at least, his morning's work to prepare them and set them in order;... read more