Note: the sense of this section of the chapter has to do with the visible angelic presence preventing the Egyptians from catching up with the Israelites.
A.15 And the LORD said unto Moses, Wherefore criest thou unto me? speak unto the children of Israel, that they go forward: 16 But lift thou up thy rod, and stretch out thine hand over the sea, and divide it: and the children of Israel shall go on dry ground through the midst of the sea. 17 And I, behold, I will harden the hearts of the Egyptians, and they shall follow them:
B. and I will get me honour upon Pharaoh, and upon all his host, upon his chariots, and upon his horsemen.
C.18 And the Egyptians shall know that I am the LORD,
B’. when I have gotten me honour upon Pharaoh, upon his chariots, and upon his horsemen.
A’. 19 And the angel of God, which went before the camp of Israel, removed and went behind them; and the pillar of the cloud went from before their face, and stood behind them: 20 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.