The Song of the Sea declares: "The depths covered them" (Exodus 15:5). The Mekhilta asks an obvious but brilliant question: are there really depths at the bottom of the sea? The Israelites had just crossed on dry ground — the seabed was exposed, solid, walkable. So what does the verse mean by "depths" covering the Egyptians?
The answer reveals a cosmic dimension to the miracle that goes far beyond a simple wall of water collapsing. According to the Mekhilta, the lower depths — the subterranean waters beneath the earth itself — rose upward to meet the upper depths of the sea. The tehomot (primordial deep waters) that exist beneath the earth's crust surged up through the dry seabed just as the walls of water crashed in from the sides.
The Egyptians were therefore attacked from below and above simultaneously. The waters did not simply return to their normal position. The deep called to the deep. Subterranean forces that had been sealed beneath the earth since creation erupted upward, while the piled waters of the sea came crashing down. The torrents embattled the Egyptians from every direction.
This image transforms the splitting of the sea from a dramatic natural event into a full-scale cosmic upheaval. God did not merely move water out of the way and then move it back. He summoned the primordial depths themselves — the same tehom that covered the earth before creation in (Genesis 1:2) — to rise from below and participate in the judgment. The very foundations of the earth opened up to swallow Pharaoh's army.