God's appearance in the world sparks a dramatic reaction in nature, especially during critical moments of salvation. At the splitting of the Red Sea, this interaction reached a poetic peak. When God revealed Himself over the waters, the sea reacted as if it possessed sight, looking upon God and fleeing in retreat [מצודת דוד, שטיינזלץ]. This was not a gentle parting; the waters experienced deep fear, trembling, and quaking [מצודת ציון, מצודת דוד, שטיינזלץ]. Even the darkest, most hidden depths of the ocean shook and split open before Him [רד״ק, מצודת ציון]. The repeated descriptions of this fear serve to magnify the sheer power and scale of the event [מצודת דוד, מאירי].
Commentators differ on the exact moment this massive reaction took place. The primary approach suggests this panic occurred when God drove the sea back with a fierce east wind to split the waters. Alternatively, this profound trembling might describe the morning hours when the sea violently crashed back to its natural state to cover the pursuing Egyptians, even as the Israelites continued to walk safely on dry land [אבן עזרא].
On a deeper level, the splitting of the sea mirrors the very creation of the world. Just as God's spirit hovered over the waters at the dawn of time, gathering the deep to reveal dry land, the waters of the Red Sea saw God and trembled to expose a dry path. This parallel suggests that the entire act of creation was ultimately set in motion for the sake of Israel [אלשיך].
From a philosophical standpoint, the idea of the waters seeing God represents physical nature completely surrendering to its Divine source. God is the root of all existence. When He chooses to suspend the natural laws of a specific element, He reveals Himself through the spiritual root of that very element. By revealing Himself over the sea through the spiritual essence of water, the physical waters recognized their Divine origin. Faced with their Creator, their natural properties dissolved instantly, leaving the depths to shudder and quake [מלבי״ם].