John Gill Commentary Exodus 14:26

"And Jehovah said unto Moses, Stretch out thy hand over the sea, that the waters may come again upon the Egyptians, upon their chariots, and upon their horsemen." — Exodus 14:26 (ASV)

And the Lord said to Moses
Out of the pillar of fire and of the cloud, when the Egyptians were in all the confusion before described, and about to make the best of their way back again:

Stretch out your hand over the sea ;
with his rod in it, by which all the wonders were worked, and particularly by which the sea had been divided, and now it must be used to a different purpose:

that the waters may come again upon the Egyptians, upon their chariots,
and upon their horsemen ;
the waters which stood upright as a wall, on the right and left, might be no longer kept in such a position, but fall down upon the Egyptians, their chariots and horsemen, being higher than they.