The price set on the rising self is the cutting away of desire. Foreskins stand for the outer craving that wraps the inner essence, and the hundred of them is the full removal of that grasping before the true self can be joined to what it longs for. What the ego on its throne intends as a trap becomes the very work that frees a person, for the strange intruding thoughts it sends to destroy the awakening mind are exactly what that mind was meant to overcome.
The higher nature does not fall by facing them. It grows by stripping the outer want away and finding the essence underneath, so the scheme meant to end the rising life is the doorway into it.
Philistines: the strange, intruding thoughts that press in from outside the settled mind
Foreskins: the outer covering of desire that wraps and hides the inner essence
David: the rising higher nature within a person, moving up against the lower mind
Saul: the ego seated on the throne, ruling the old life and guarding it