The City of God, Volume I

At this point Augustine introduces a sustained critique of theurgy—the system of ritual practices that certain Platonists, including Porphyry, recommended for the purification of the soul. Theurgy claims to secure divine assistance through prescribed rites and invocations, yet Porphyry himself admitted that these practices cannot purify the intellectual soul, which apprehends truth. At most, theurgy might cleanse the lower “spiritual” part of the soul, but even this limited purification cannot grant immortality or lead the soul back to the Father. Porphyry further acknowledged that theurgic arts involve dealing with powers that envy the soul’s purity—powers that can be bound by the incantations of the wicked and thus prevented from doing good to the righteous. Augustine exposes the absurdity of this position: if these were truly good gods, a well-disposed person seeking purification would surely have more influence with them than an envious person seeking to hinder him. The very fact that theurgic deities can be terrified and constrained by wicked men proves that they are not gods at all but deceiving demons, who transform themselves into angels of light to entangle souls in the worship of many false gods.

Augustine provides a detailed analysis of Porphyry’s letter to Anebo the Egyptian, a document that reveals the philosopher’s deep ambivalence about theurgic practices. Writing in the character of an inquirer, Porphyry exposes the contradictions and absurdities of the magical arts. He expresses astonishment that sacrifices can compel the gods to do men’s bidding, that visible celestial bodies are considered divine despite being corporeal, that priests must avoid certain foods while the gods they serve are attracted by sacrificial fumes. He relates how a certain Chæremon described the Egyptian mysteries of Isis and Osiris as having such power that the gods could be coerced by threats—threats to divulge the mysteries or scatter the members of Osiris. Porphyry rightly marvels that men should utter wild and impossible threats against the heavenly gods and that these threats should prove effective. He concludes that such things must be the work of deceitful spirits who simulate gods and dead men but are in fact demons. Augustine commends Porphyry’s skeptical observations but laments that the philosopher did not take the final step of renouncing these practices entirely and embracing the worship of the one true God.

Having distinguished the true miracles of God from the deceptive marvels of theurgy, Augustine proceeds to elaborate on the ministry of angels and the providence of God. It has pleased Divine Providence that the law enjoining the worship of one God should be given through the disposition of angels. In this administration, the person of God Himself visibly appeared, not in His proper substance—which ever remains invisible to mortal eyes—but by infallible signs furnished by creation in obedience to its Creator. He made use of human speech, uttering words syllable by syllable, though in His own nature He speaks not in a bodily but in a spiritual manner, not to sense but to the mind. What He says is accurately heard by the mental ear of His ministers and messengers, who are immortally blessed in the enjoyment of His unchangeable truth. The directions which they receive in an ineffable manner, they execute without delay in the visible world. This law was given in conformity with the age of the world, containing at first earthly promises which symbolized eternal ones. These eternal blessings few understood, though many participated in the celebration of their visible signs. Nevertheless, both the words and the visible rites of that law enjoin the worship of one God—not one of a crowd of gods, but Him who made heaven and earth, and every soul and every spirit which is other than Himself. He created all things; all else was created; and, both for being and well-being, all things need Him who created them. Thus, the ministry of angels is the instrument by which God executes His providence in the world, guiding the education of the human race from earthly to heavenly things, and from the visible to the invisible.

This divine providence, mediated through the holy angels, stands in stark contrast to the activities of the demons. Augustine therefore establishes a criterion for choosing between competing miraculous claims. We are faced with a choice between two types of spirits: those who demand that we pay them divine honour and sacrifice to them, and those who teach us to render holy service, not to themselves, but to God alone. The former perform marvels to induce us to worship them; the latter perform miracles to induce us to worship the one God. The former do not forbid us to worship God, while the latter forbid us to worship themselves. Which angels are we to believe regarding the way to eternal life? If neither party had wrought miracles, but had merely uttered commands, a godly mind would have been at no loss to discern which command proceeded from proud arrogance and which from true religion. If miracles had been wrought only by those who demand sacrifice for themselves, while those who forbade this and enjoined sacrificing to the one God only thought fit entirely to forego the use of visible miracles, the authority of the latter would still have been preferred by all who use their reason. But since God, for the sake of commending to us the oracles of His truth, has wrought miracles of surpassing grandeur through the immortal messengers who proclaim His majesty and not their own pride, who is so unreasonable as not to choose and follow the truth when he finds it heralded by even more striking evidences than falsehood? We must trust the angels who forbid us to worship them and direct us to God, rather than those who demand worship for themselves. The miracles of the true God are greater and lead to eternal blessedness, whereas demonic miracles lead to idolatry and eternal misery.

Augustine illustrates the superiority of the true miracles by recounting the history of the Ark of the Covenant. The law of God, given through the ministry of angels and commanding exclusive worship of the one true God, was deposited in the ark as a testimony to His will. This ark accompanied the people through the wilderness, preceded by the sign of cloud by day and fire by night. When the people crossed the Jordan River, the waters parted before the ark. When they encircled the walls of Jericho, the fortifications fell without human assault. When the ark was captured by the Philistines and placed in the temple of their god Dagon, the idol was found prostrate and shattered before it. These wonders, though small matters for omnipotence, were mighty to instruct and terrify men, confirming the religion that forbids sacrifice to any but the one God. They attest the presence of divinity at the time predicted, and commend that religion which forbids the offering of sacrifice to any celestial, terrestrial, or infernal being, and commands it to be offered to God only, who alone blesses us by His love for us, and by our love to Him.