Bethshemesh means house of the sun, the seat of light in the body, and the men there are the faculties that pried open the ark, the innermost sacred vessel of the self, without being prepared to bear what it holds. To look into the ark is to force the deep inner power with the curious surface mind rather than approach it purified, and the flesh cannot survive the direct current: the lower faculties are struck down. The slaughter is inward, the collapse of the parts of a person that reached for the highest force from an unready, outward state, and the mourning that follows is the self's grief over what it lost by grasping the holy carelessly.
Bethshemesh: the house of the sun, the seat of light within the body where the inner radiance dwells.
Ark: the innermost sacred vessel of the self, the deep container of divine power that the unready mind must not pry open.