The mind and the whole inner assembly break into song once the crossing is made, and understanding along with the ego that rode it is cast into the deep truth. Moses is the description of a person's own mind, and Israel is Isis the spirit, Ra the mind, and El the god within, joined in one voice. The horse is understanding and its rider the proud self that mounts it; both are thrown into the sea, the deep truth that swallows the false and leaves only the song. What drowns in that water is not a person but the overreaching intellect and the ego perched upon it.
When the deep truth takes down understanding and the self that rode on it, the mind and all its inner children are freed into the music of the crossing.
Moses: the description of a person's own mind leading the way through
Israel: Isis the spirit, Ra the mind, and El the god within, joined as one
Horse: understanding, the mount the self climbs upon
The sea: the deep truth that swallows the false and drowns the proud intellect