Egypt is the body held under bondage to matter, and its firstborn are the first fruits of the lower mind, the earliest and strongest attachments the material self produces. When the higher call moves through a person, these die from top to bottom, from the ruling thought enthroned as Pharaoh down to the meanest habit grinding at the mill, and even the animal appetites go with them. The firstborn is what the flesh loves most, its chosen heir, and it is precisely this that must fall before liberation.
Every grade of the outer man is touched, the proud governing ego and the humblest servile compulsion alike, none exempt. The old self does not survive the crossing out of bondage; its favored offspring, high and low, all pass away so the deeper life can go free.
Egypt: the body held in bondage to matter and the material world
Firstborn: the first and strongest attachments the lower self produces, what the flesh loves most
Pharaoh: the ruling thought of the ego enthroned over the body
Throne: the seat of command the material mind takes within a person
Mill: the low, grinding round of servile habit at the bottom of the outer man
Beasts: the animal appetites of the body that fall with the rest of the lower self