Chapter XV. The Arians, inasmuch as they assert the Son to be “of another substance,” plainly acknowledge substance in God. The only reason why they avoid the use of this term is that they will not, as Eusebius of Nicomedia has made it evident, confess Christ to be the true Son of God. 123. How can the Arians deny the substance of God? 2309 How can they suppose that the word “substance” which is found in many places of Scripture ought to be debarred from use, when they themselves do yet, by saying that the Son is “ ἑτεροούσιος ,” that is, of another substance, admit substance in God? 124. It is not the term itself, then, but its force and consequences, that they shun, because they will not confess the Son of God to be true [God]. 2310 For though the process of the divine generation cannot be comprehended in human language, still the Fathers judged that their faith might be fitly distinguished by the use of such a term, as against that of “ ἑτεροούσιος ,” following the authority of the prophet, who saith: “Who hath stood in the truth ( substantia ) of the Lord, and seen His Word?” 2311 Arians, therefore, admit the term “substance” when it is used so as to square with their blasphemy; contrariwise, when it is adopted in accordance with the pious devotion of the faithful, they reject and dispute against it. 125. What other reason can there be for their unwillingness to have the Son spoken of as “ ὁμοούσιος ,” of the same substance, with the Father, but that they are unwilling to confess Him the true Son of God? This is betrayed in the letter of Eusebius of Nicomedia. “If,” writes he, “we say that the Son is true God and uncreate, then we are in the way to confess Him to be of one substance ( ὁμοούσιος ) with the Father.” When this letter had been read before the Council assembled at Nicæa, the Fathers put this word in their exposition of the Faith, because they saw that it daunted their adversaries; in order that they might take the sword, which their opponents had drawn, to smite off the head of those opponents’ own blasphemous heresy. 2312 126. Vain, however, is their plea, that they avoid the use of the term, because of the Sabellians; 2313 whereby they betray their own ignorance, for a being is of the same substance ( ὁμοούσιον ) with another, not with itself. Rightly, then, do we call the Son “ ὁμοούσιος ” (of the same substance), with the Father, forasmuch as that term expresses both the distinction of Persons and the unity of nature. 127. Can they deny that the term “ οὐσία ” is met with in Scripture, when the Lord has spoken of bread, that is, “ ἐπιούσιος ,” 2314 and Moses has written “ ὑμεῖς ἔσεσθέ μοι λαὸς περιούσιος ”? 2315 What does “ οὐσία ” mean, whence comes the name, but from “ οὖσα ἀεί ,” 2316 “that which endures for ever? For He Who is , and is for ever, is God; and therefore the Divine Substance, abiding everlastingly, is called οὐσία . Bread is ἐπιούσιος , because, taking the substance of abiding power from the substance of the Word, it supplies this to heart and soul, for it is written: “And bread strengtheneth man’s heart.” 2317 128. Let us, then, keep the precepts of our forefathers, nor with rude and reckless daring profane the symbols bequeathed to us. That sealed book of prophecy, whereof we have heard, neither elders, nor powers, nor angels, nor archangels, ventured to open; for Christ alone is reserved the peculiar right of opening it. 2318 Who amongst us dare unseal the book of the priesthood, sealed by confessors, and long hallowed by the testimony of many? 2319 They who have been constrained to unseal, nevertheless have since, respecting the deceit put upon them, sealed again; they who dared not lay sacrilegious hands upon it, have stood forth as martyrs and confessors. How can we deny the Faith held by those whose victory we proclaim? 2309     i.e. how can they say there is no Divine Substance, that the use of the term “substance” is illegitimate? 2310     Or to be the true Son of God, Son by nature, not by adoption. 2311     Jer. xxiii. 18 . 2312     Cf. 1 Sam. xvii. 51 . 2313     The Sabellians reduced the distinction of Persons in the Trinity to a distinction of three different self-manifestations of one and the same Person, appearing at different times in different aspects or characters, as “one man in his time plays many parts.” They, therefore, would mean, if they said that the Son was ὁμοούσιος with the Father, that He was identical with Him. Another perverse use of the term supervened upon the argument that if the Father and the Son were ὁμοοὐσιοι there must be some οὐσία , identical with neither, but in which both, so to speak, had a share, by virtue of participation in which they existed and were what they were—a theory which adapted the Platonic doctrine of Universal Ideas to expound the mysteries of the Godhead. It was the perverse use of the term by such persons as Paul of Samosata (condemned by the Synod of Antioch, 269 a.d. ) that caused it to be received at first with suspicion even by the orthodox at the Nicene Synod in 325 a.d. The true doctrine would be to this effect, that in relation to the Persons, the Godhead is not a separate, more comprehensive entity, existing independently, and the fount of existence to each and all of the Persons—not as the Platonic αὐτάνθρωπος (ideal or archetypal man), for example, to the πολλοὶ ἄνθρωποι (sundry individuals), but is in each of the Persons fully and completely, yet without destruction of its unity. The Godhead is a πρώτη οὐσία , a single, individual substance. So also is each One of the Three Persons—but their inter-relation is such that neither is the Godhead anything apart from them, nor they anything apart from the Godhead or from each other. It is the Three together that constitute the One Οὐσία or Essence, it is the definition of this Essence that applies to Each of them equally, without difference, whilst Each Person retains His Personal characteristics and Personal (not natural or substantial) “ differentia. ” Speaking logically, the Three Persons are “of one definition;” speaking metaphysically, they are “of one Essence.” Now both “of one definition” and “of one essence” may be rendered by ὁμοούσιοι . 2314     S. Matt. vi. 11 . ἐπιούσιος ="required for our subsistence, proper for our sustenance.” See Alford in loc. 2315     Ex. xix. 6 . 2316     The derivation is philologically incorrect, for οὐσία is formed upon the fem. of the pres. part. of εἶναι , but for all that it embodies a certain truth, inasmuch as οὐσία in its abstract use denotes simple existence, without reference to conditions. 2317     Ps. civ. 15 . The term ἐπιούσιος has a spiritual import, inasmuch as the life of the body, supported by bread, is not all but should be subordinate to the spiritual life—the healthy body to be the instrument and vehicle of the healthy soul, for man’s real life (though he is not apt to think it such) is not dependent on bread alone —his whole existence is not material, though one side of it is. St. Ambrose, however, seems rather disposed to overlook the physical material bread (which we are certainly taught to pray for) for the sake of the supra-sensible Bread of Heaven and Food of Angels. 2318     Rev. v. 5 . 2319     A reference to the Synod of Ariminum. See Bk. I. xiii. 122.