The Mekhilta DeRabbi Yishmael offers a vivid image of what happened to the Egyptians at the bottom of the Red Sea. The Torah says "the depths were congealed in the heart of the sea" (Exodus 15:8), using the Hebrew word "kafu." The rabbis connect this word to "kippah" — a dome or an arch — and from this linguistic link, they reconstruct the scene.
God made the waters form a dome over the Egyptians, like an arched ceiling closing in from above. The sea did not simply crash down on them in a chaotic flood. It curved over them, sealing them beneath a vault of water.
The Mekhilta then offers an anatomical analogy to explain the shape. A human heart has two chambers and an arch connecting them. Just as the heart is structured with an arching form, so God "arched the sea over them." The waters formed a living architecture — a dome of ocean pressing down with the same organic structure as the human body's most vital organ.
This image transforms the crossing of the Red Sea from a simple parting-and-closing into something far more deliberate. The Egyptians were not merely drowned. They were entombed beneath a carefully constructed vault. The sea became a building — walls, ceiling, and all — with the Egyptian army trapped inside its chambers. The language of the Torah, read closely enough, reveals that even in destruction, God's hand shaped the waters with precision and purpose, not chaos.