Novatian

“ But when the Lord says that God is a Spirit, I think that Christ spoke thus of the Father, as wishing that something still more should be understood than merely that God is a Spirit. For although, in His Gospel, He is reasoning for the purpose of giving to men an increase of intelligence, nevertheless He Himself speaks to men concerning God, in such a way as they can as yet hear and receive ”

“ God is for this reason called Fire, that fear may be struck into the hearts of a sinful people, by suggesting to them a Judge; so in the New Testament He is announced as Spirit, that, as the Renewer and Creator of those who are dead in their sins, He may be attested by this goodness of mercy granted to those that believe. ”

“ For we find it to be written that God is called Love, and yet from this the substance of God is not declared to be Love; and that He is called Light, while in this is not the substance of God. But the whole that is thus said of God is as much as can be said, so that reasonably also, when He is called a Spirit, it is not all that He is which is so called; but so that, while men’s mind by understanding makes progress even to the Spirit itself, being already changed in spirit, it may conjecture God to be something even greater through the Spirit. ”