Anima in ipsum perfecte dominabitur quantum ad hoc quod ipsum vivificet (see further Chap. LXXXVI). This axiom seems to furnish the key to the whole situation of risen humanity. No longer dependent on energy supplied from external nature in the shape of food and oxygen, man's soul shall breathe its own spiritual energy direct into his body. The case is otherwise with mortal man. Whatever in us the will insists on having done, even the very act of the will so insisting, is paid for out of the store of physical energy belonging to the body, and latent somewhere in the animal system. Witness the reaction and prostration that follows sooner or later upon every heroic effort. The effort is only made by what we may call a forced loan of bodily energy, raised by the will, or rather by the man willing, for the will is not a motor power distinct, but belongs to the 'form' of the body. But in man risen and immortal, the soul (to use an expressive vulgarism) shall run the body, not merely by directing and whipping up bodily energy, but by communication to the body of the soul's own energy, proper to it as a spiritual substance, the energy of a spirit either isaggelos (which Luke xx, 36, seems rather to imply), or minished a little less than the angels (Ps. viii, spoken of mortal man).
Of God and His Creatures: 4.85