On The Holy Trinity by St. Augustine
Chapter 4.--What Universal Nature Teaches Us Concerning God.
6. Let us, then, now seek the Trinity which is God, in the things themselves that are eternal, incorporeal, and unchangeable; in the perfect contemplation of which a blessed life is promised us, which cannot be other than eternal. For not only does the authority of the divine books declare that God is; but the whole nature of the universe itself which surrounds us, and to which we also belong, proclaims that it has a most excellent Creator, who has given to us a mind and natural reason, whereby to see that things living are to be preferred to things that are not living; things that have sense to things that have not; things that have understanding to things that have not; things immortal to things mortal; things powerful to things impotent; things righteous to things unrighteous; things beautiful to things deformed; things good to things evil; things incorruptible to things corruptible; things unchangeable to things changeable; things invisible to things visible; things incorporeal to things corporeal; things blessed to things miserable. And hence, since without doubt we place the Creator above things created, we must needs confess that the Creator both lives in the highest sense, and perceives and understands all things, and that He cannot die, or suffer decay, or be changed; and that He is not a body, but a spirit, of all the most powerful, most righteous, most beautiful, most good, most blessed.