אתיקה, חלק I, משפט 26

That by which things are said to be conditioned to act in a particular manner is necessarily something positive (this is obvious); therefore both of its essence and of its existence God by the necessity of his nature is the efficient cause (Props. xxv. and xvi.); this is our first point. Our second point is plainly to be inferred therefrom. For if a thing, which has not been conditioned by God, could condition itself, the first part of our proof would be false, and this, as we have shown is absurd.