For because there is one God, it is thus said to us through the prophet: I am God, and there is no other besides me: just and saving, and there is no other besides me: be converted to me, and you shall be saved, for from the end of the earth I am God, and there is no other. By myself I swear, for justice shall go forth (var. hath gone forth) out of my mouth, and my words shall not be turned back: for to me every knee shall bow (var. hath bowed), and every tongue shall swear (var. hath sworn) by God (Isa. 45:21 ff.). Behold, God, who in this passage, saying that He alone is God, testifies that there is no other besides Him. But if anyone here should refuse to take the whole Trinity, he will be compelled to assign this voice to the Son alone.
For who is God besides whom there is no other, except He to whom Isaiah says: Egypt hath laboured, and the merchandise of Ethiopia and the Sabaim, tall men, shall pass over to thee, and shall be thine: they shall follow thee bound in fetters, and they shall adore thee, and shall make supplication to thee: because God is in thee, and there is no God besides thee; for thou art God, and we knew it not, the God of Israel, the Saviour. They shall be confounded and ashamed, all who oppose Him, and shall go with confusion (Isa. 45:14 ff.). Behold, in Him is God, and besides Him there is no God, and He is the God of Israel, the Saviour. But above, He who said: I am God, and there is no other besides me, added: Just and saving, there is no other besides me.
But who is just, except He to whom David says: Thou hast loved justice, and hated iniquity (Ps. 44:8)? And who is saving, except He of whom the angel spoke to Joseph in a dream, saying: Joseph, son of David, fear not to take unto thee Mary thy wife, for that which is born in her is of the Holy Spirit: and she shall bring forth a son, and thou shalt call His name Jesus; for He shall save His people from their sins (Matt. 1:20)? But to whom is it fitting to say: Be converted to me, and you shall be saved, for from the end of the earth I am God, and there is no other (Isa. 45:22), except to the Son?
of whom David says: All the ends of the earth shall remember, and shall be converted to the Lord, and all the kindreds of the nations shall adore in His sight (Ps. 21:28). And that which follows: By myself I swear—who is to be believed to say this, except He who is found to have thus sworn to Abraham before? But this one they assert to be not the Father, but the Son—those who contend that the Son is to be proclaimed less than the Father according to the divine nature. But whether this God, who swears by Himself, has one greater than Himself, blessed Paul shows us, who, writing to the Hebrews, says: For God, making promise to Abraham, because He had no one greater by whom He might swear, swore by Himself, saying:
Blessing I will bless thee, and multiplying I will multiply thee (Heb. 6:13-14). This God, therefore, who swears by Himself because He has no one greater by whom He might swear—let us see what follows: For justice, He says, shall go forth out of my mouth, and my words shall not be turned back: for to me every knee shall bow (var. hath bowed), and every tongue shall swear (var. hath sworn) by God (Isa. 45:23). From whose mouth, then, did justice go forth, except His of whom Isaiah said: A rod shall come forth out of the root of Jesse, and a flower shall rise up out of his root, and the spirit of the Lord shall rest upon Him (Isa. 11:1). And a little after: He shall judge the poor in justice, and shall reprove in equity for the meek of the earth (Ibid., 4).
There follows then: This God, besides whom there is no other, says also: My words shall not be turned back. But whose voice is this, except His who in the Gospel says: Heaven and earth shall pass away, but my words shall not pass away (Matt. 24:35)? Likewise He adds, this God besides whom there is no other, and says: For to me every knee shall bow, and every tongue shall swear by God. But concerning whom this ought to be understood, Paul, taught by the mastery of Christ, shows us, who, writing to the Romans, thus says: For none of us lives to himself, and no one dies to himself. For whether we live, we live to the Lord; or whether we die, we die to the Lord. Whether therefore we live, or whether we die, we are the Lord's (Rom.
14:7-8). And, that he might show he had said this of Christ, he added: For to this end Christ both died and rose again, that He might be Lord both of the dead and of the living. But thou, why dost thou judge thy brother? or thou, why dost thou despise thy brother? For we shall all stand before the tribunal of God (Rom. 14:9-10). And immediately he adds this prophetic testimony, saying: For it is written: As I live, saith the Lord, that to me every knee shall bow, and every tongue shall confess to God (Isa. 45:24). And that we shall stand before the tribunal of Christ, he himself again testifies, saying: For we must all be made manifest before the tribunal
of Christ, that each one may receive the proper things of the body, according as he hath done, whether good or evil (2 Cor. 5:10). That to Him too every knee is to be bowed, the same apostle teaches, saying: That in the name of Jesus every knee should bow, of those in heaven, on earth, and under the earth: and that every tongue should confess that the Lord Jesus Christ is in the glory of God the Father (Phil. 2:10-11). Now, then, let us again consider all the things that were said above. God says: I am God, and there is no other besides me. And in the person of the Son Isaiah says: Because in thee is God, and besides thee there is no God; for thou art God, and we knew it not, the God of Israel, the Saviour (Isa. 45:15). But the God of Israel is one God.
But there follow the other things which by the aforesaid testimonies we showed to pertain to the Son: for He Himself swears by Himself, having no one greater; He Himself saves His people; He Himself judges justly; to Him every knee bows, of those in heaven, on earth, and under the earth; to Him every tongue confesses, from whom the recompense of deeds is to be rendered. He therefore, of whom all these things are said, says through the prophet: I am God, and there is no other besides me. Do we then so take this God, besides whom there is no other, to be the Son alone, that we separate from Him the Father and the Holy Spirit? Far be it: for this is impossible. For besides God the Father, God the Son is not, because He is of the Father, and is in the Father.
Besides the Father and the Son, the Holy Spirit is not, because He is the Spirit of the Father and of the Son, and is in the Father and in the Son. Whence it is recognized that this Trinity is one Lord God, of whom it is said: Hear, O Israel, the Lord thy God, the Lord (var. God) is one (Deut. 6:4). And: Thou shalt adore the Lord thy God, and Him only shalt thou serve. To this Lord also the prophet Isaiah says: O Lord, besides thee we know no other, we name thy name. But this name our Saviour showed, saying to His disciples: Go, teach all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit (Matt. 28:19).
This is the name of the Lord, besides whom we know no other, and by the naming of whose name we are freed from death, delivered from the power of darkness, that we may be transferred into the kingdom of the Son. In the Father, therefore, and the Son and the Holy Spirit we receive the unity of substance; we dare not confound the persons. For the blessed apostle John testifies, saying: There are three that bear witness in heaven, the Father, the Word, and the Spirit; and these three are one (1 John 5:7). Which also the most blessed martyr Cyprian confesses, in his epistle On the Unity of the Church, saying: He who breaks the peace and concord of Christ acts against Christ; he who gathers elsewhere, apart from the Church, scatters the Church of Christ.
And in order to show that there is one Church of one God, he at once inserted these testimonies from the Scriptures. The Lord says: 'I and the Father are one.' And again: Of the Father and the Son and the Holy Spirit it is written: 'And these three are one.' For in the book on the Lord's Prayer as well, in order to show that the Trinity is of one Godhead and has no diversity among its members, he recalled that Daniel and the three children were accustomed to pour out prayer at the recurring intervals of the three hours. There too, both in the course of the three hours and in the beginning of a single prayer, he clearly showed that one God is the Trinity.
Therefore we do not worship one God out of three parts, but, holding fast the rule of the apostolic faith, we confess the Son to be perfect and co-eternal, begotten of the perfect and eternal Father, without beginning, not unequal in power, and equal in nature. We confess also that the Holy Spirit is nothing other than God, neither different from the Son nor from the Father, nor confounded in the Son nor in the Father. For the Spirit of the Father and of the Son is one and the same, proceeding wholly from the Father, subsisting wholly in both, and He is not divided in each individually, because He is inseparably common to both.