תהלים, פרק ק״ו, פסוק י״א

The miraculous parting of the Red Sea served a dual purpose. It was not merely a path of escape for the Israelites, but rather the means to bring about the complete ruin of Egyptian power. Those who chased the fleeing nation were not ordinary foes. There is a distinct difference between a passive enemy and an active adversary who goes out with the specific intent to wage war and inflict harm [מלבי״ם]. The Egyptians fell into this latter, more dangerous category, ruthlessly pursuing the Israelites to strike them down [אבן עזרא, מאירי].

God's use of the sea waters accomplished more than simply blocking the Egyptian advance to keep the Israelites safe. Instead, the waters returned in full force, completely covering and drowning the pursuing army [ביאור שטיינזלץ]. The primary approach among commentators is that this destruction was absolute. The entire Egyptian military force, including Pharaoh and all his troops, was wiped out in the sea without a single survivor. However, an alternative perspective suggests a slight exception to this total annihilation. While every active soldier who pursued the Israelites perished, exactly one enemy was left alive: Pharaoh himself [אלשיך].