Ante-Nicene Fathers, Vol II:
THEOPHILUS: Chapter V.—The Invisible God Perceived Through His Works.

Chapter V.—The Invisible God Perceived Through His Works.

For as the soul in man is not seen, being invisible to men, but is perceived through the motion of the body, so God cannot indeed be seen by human eyes, but is beheld and perceived through His providence and works. For, in like manner, as any person, when he sees a ship on the sea rigged and in sail, and making for the harbour, will no doubt infer that there is a pilot in her who is steering her; so we must perceive that God is the governor [pilot] of the whole universe, though He be not visible to the eyes of the flesh, since He is incomprehensible. For if a man cannot look upon the sun, though it be a very small heavenly body, on account of its exceeding heat and power, how shall not a mortal man be much more unable to face the glory of God, which is unutterable? For as the pomegranate, with the rind containing it, has within it many cells and compartments which are separated by tissues, and has also many seeds dwelling in it, so the whole creation is contained by the spirit 532 of God, and the containing spirit is along with the creation contained by the hand of God. As, therefore, the seed of the pomegranate, dwelling inside, cannot see what is outside the rind, itself being within; so neither can man, who along with the whole creation is enclosed by the hand of God, behold God. Then again, an earthly king is believed to exist, even though he be not seen by all; for he is recognised by his laws and ordinances, and authorities, and forces, and statues; and are you unwilling that God should be recognised by His works and mighty deeds?

Footnotes

The reference here is not to the Holy Spirit, but to that vital power which is supposed to be diffused thorughout the universe. Comp. book ii. 4.