And it came between the camp of the Egyptians and the camp of Israel; and it was a cloud and darkness to them, but it gave light by night to these: so that the one came not near the other all the night.
All Commentaries on Exodus 14:20 Go To Exodus 14
Gregory the Theologian
AD 390
Therefore this darkness of the body has been placed between us and God, like the cloud of old between the Egyptians and the Hebrews. This is perhaps what is meant by “He made darkness his separate place,” namely, our dullness, through which few can see even a little.