Ch. 17 - "God Neither the Form of a Body Nor a Force in a Body" From the "Compendium of Theology" by St. Thomas Aquinas

Caput 17 Quod impossibile est esse formam corporis, aut virtutem in corpore

CHAPTER 17 GOD NEITHER THE FORM OF A BODY NOR A FORCE IN A BODY

Neque etiam est possibile ipsum esse formam corporis, aut aliquam virtutem in corpore. Cum enim omne corpus mobile inveniatur, oportet corpore moto, ea quae sunt in corpore moveri saltem per accidens. Primum autem movens non potest nec per se nec per accidens moveri, cum oporteat ipsum omnino esse immobile, ut ostensum est. Impossibile est igitur quod sit forma, vel virtus in corpore.

God cannot be the form of a body or any kind of force existing in a body. For, since all bodies are found to be mobile, whatever is present in a body must be moved, at least per accidens or concomitantly, if the body itself is moved. The first mover, however, cannot be moved either per se or per accidens, for it must be absolutely immobile, as has been shown. Therefore God cannot be a body or a force in a body.

Item. Oportet omne movens, ad hoc quod moveat, dominium super rem quae movetur, habere: videmus enim quod quanto magis virtus movens excedit virtutem mobilis, tanto velocior est motus. Illud igitur quod est omnium moventium primum, oportet maxime dominari super res motas. Hoc autem esse non posset, si esset mobili aliquo modo alligatum; quod esse oporteret, si esset forma eius, vel virtus. Oportet igitur primum movens neque corpus esse, neque virtutem in corpore, neque formam in corpore. Hinc est quod Anaxagoras posuit intellectum immixtum, ad hoc quod imperet, et omnia moveat.

Again, in order to move an object, every mover must have dominion over the thing that is moved. For we observe that motion is more rapid in proportion as the motive force exceeds the resisting force of the mobile object. Therefore that which is the very first among all movers, must predominate supremely over all the things moved. But this would be impossible if the mover were in any way attached to the mobile object, as it would have to be if it were the form or motive power of the latter. Consequently the first mover cannot be a body or a force in a body or a form in a body. This is why Anaxagoras postulated an intelligence liberated from matter, that it might rule and move all things.”