Paul read the Red Sea as a baptism: the old life on one side, the new on the other, and the power that held you buried in between.
The Shadow
Israel stood trapped between deep water and the most powerful army on earth, and their faith was not impressive. They accused Moses and said slavery would have been better. The crossing did not happen because Israel's faith was strong enough. It happened because God decided to fight. Moses gave the strangest command a people facing destruction has ever received: do not be afraid; stand still, and see the salvation of the Lord.
God parted the water, Israel walked through on dry ground, and when the last foot touched the far shore, the sea closed like a grave over Egypt. By morning Israel looked back and saw no regrouping enemy. The threat was not managed or pushed back. It was over.
The Fulfillment
Paul does not say “look at Israel's faith and model it.” He says all were baptized into Moses in the cloud and in the sea. He read the crossing as a baptism: the old life on one side of the water, the new life on the other, and in between, something has to die. What died was not just an army. It was the structure of Israel's captivity, the power that said you belong to us and always will.
That is the picture of the cross. Our old man was crucified with Him, that we should no longer be slaves of sin. Done away with, not put on a leash. Buried with Him in baptism and raised with Him through faith. The old man did not make it across the water.
Him All Along
If you stand on the far shore and still hear hoofbeats, the whisper that you have not really changed, remember which side of the water that voice is on. God buried what was behind you while you did exactly nothing to help. The crossing has already happened. You are already on the other side, and what He buries stays buried.