In the first reading we are reminded from Isaiah, about the Red Sea. He uses that as an example, and he talks about water in this example. And he reminds them that the waters were opened so that the Lord's people, the people He wished to form, the people He had chosen to be His own for a purpose, to announce His praise, that's the purpose and of course be His people, water was separated. Only God can do that and He provided a path to life, a new life, a new life beyond the edge of the sea, into the desert where they would begin their formation.
And as those that would destroy the people God had formed for Himself, not for themselves, but for Himself, and for life, He used those same waters to snuff them out like a wick. And we know what their formation was like in the desert. We know about the complaining, we know about the fleshpots, where's our fleshpots. we know about the rebellion, we know about the golden calf, we know about all those time that the people resisted receiving formation. Even Moses said, "is this is how you are going to treat me, kill me." These people. And they needed so much formation, that even after 40 years, only 2 of them got to enter the promised land. Joshua and Caleb. The rest were deemed unworthy. Even after all of that. Lots of formation over a long period of time. And it's the same with us.