Charles Ellicott 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. —Or, The Lord had said. Probably the command was given as soon as the Israelites were safe across. It would take some hours for the north-west wind to bring back the waters of the Bitter Lakes.