Let us see whether the confession of the apostle Thomas agrees with this teaching of the Evangelist, when he says, My Lord and my God.^[1] He is therefore his God whom he acknowledges as God. And certainly he was aware that the Lord had said, Hear, O Israel, the Lord your God is one. And how did the faith of the apostle become unmindful of the principal commandment, so that he confessed Christ as God, since we are to live in the confession of the one God? The apostle, who perceived the faith of the entire mystery through the power of the resurrection, after he had often heard I and the Father are one and All things that the Father has are mine and I in the Father and the Father in me,^[2] now confessed the name of the nature without endangering the faith.

Wherefore [Scripture] says, The Lord God is one Lord. By the word Godhead it proclaims too the only-begotten God and does not divide the unity into a duality so as to call the Father and the Son two gods, although each is called God by holy writers.

The law says, Hear, O Israel, the Lord your God. It did not say speak but hear. Eve fell because she said to the man what she had not heard from the Lord her God. The first word from God says to you, hear.

Such too was the teaching of the law: Hear, O Israel, the Lord your God is one Lord, that is, unchangeable, always abiding in unity of power, always the same and not altered by any accession or diminution. Therefore Moses called him one.

What then? one may say. Were they wronged who lived before his coming? By no means, for men might then be saved even though they had not confessed Christ. For this was not required of them, but not to worship idols and to know the true God. For the Lord your God, it is said, is one Lord. Therefore the Maccabees were admired, because for the observance of the law they suffered what they did suffer;^[1] and the three children,^[2] and many others too among the Jews, having shown forth a very virtuous life and having maintained the standard of this their knowledge, had nothing more required of them. For then it was sufficient for salvation, as I have said already, to know God only, but now it is so no more. There is need also of the knowledge of Christ.

That Trinity is one God. Not that Father, Son and Holy Spirit are identically the same. But the Father is Father, the Son is Son, and the Holy Spirit is Holy Spirit, and this Trinity is one God, as it is written: Hear, O Israel, the Lord your God is one God.

Consider now for a while the passages of Scripture which force us to confess that the Lord is one God, whether we are asked about the Father alone, or the Son alone, or the Holy Spirit alone, or about the Father and the Son and the Holy Spirit together. Certainly it is written, Hear, O Israel, the Lord your God is one Lord. Of whom do you think that this is said? If it is said only of the Father, then our Lord Jesus Christ is not God. Why did those words come to Thomas when he touched Christ and cried out, My Lord and my God,^[1] which Christ did not reprove but approved, saying, Because you have seen, you have believed?^[2]

Therefore, in whatever place you may be, because you know that you have been baptized in the one name of the Father and the Son and the Holy Spirit, according to the rule promulgated by the command of our Savior, retain this rule with your whole heart, from the start and without hesitation: the Father is God, and the Son is God, and the Holy Spirit is God. This means the holy and ineffable Trinity is by nature one God, concerning whom it is said in Deuteronomy, Hear, O Israel, the Lord your God is one God, and You shall adore the Lord your God and him alone shall you serve.^[1] Indeed, . . . we have said that this one God who alone is true God by nature, is not the Father only, nor the Son only, nor the Holy Spirit only but is at one and the same time Father, Son and Holy Spirit. [Thus] we must be wary that while we say in truth that as the Father, Son, and Holy Spirit are one God, insofar as this is a unity of nature, we dare not say or believe something altogether blasphemous. [Such a blasphemous saying would be] that he who is the person of the Father is the same as either the Son or the Holy Spirit, or that he who is the person of the Son is the Father or the Holy Spirit. Or [it might be] that we dare to say or to believe that the person who is properly called the Holy Spirit in the confession of this Trinity is either the Father or the Son, something that is altogether wicked.

If one does not love God with all his heart and with all his soul, how can he care wholesomely and guilelessly for the love of his brothers, since he is not fulfilling the love of the One on whose account he has a care for the love of his brothers? The person in this condition, who has not given his whole soul to God and has not participated in his love, the craftsman of evil finds disarmed and easily overpowers.

It is a noble thing to do one’s kindnesses and duties toward the whole of the human race. But it is ever more seemly that you should give to God the most precious thing you have, that is, your mind, for you have nothing better than that. When you have paid your debt to your Creator, then you may labor for humanity, to show them kindness and to give help. Then you may assist the needy with money, or by some duty or some service that lies in the way of your ministry; by money to support him; by paying a debt, so as to free him that is bound; by undertaking a duty, so as to take charge of a trust, which he fears to lose, who has put it by in trust.

Now one who loves undoubtedly believes, and by believing each one begins to love. Finally, Abraham believed,^[1] and thus he began to love. He did not believe in part but believed all things. Otherwise he could not possess full charity, since Scripture says, Charity believes all things.^[2]

To humanity it was said, Love the Lord your God, yet the love of God is not instilled in the hearts of all. Deafer are the hearts of people than the hardest rock. The earth, in compliance with its Author, furnishes us with fruit which is not owed to us. We deny the debt when we do not give homage to the Author.

For while there remains any remnant of the lust of the flesh, to be kept in check by the rein of continence, God is by no means loved with all one’s soul. For the flesh does not lust without the soul, although it is the flesh which is said to lust, because the soul lusts carnally. In that perfect state the just man shall live absolutely without any sin, since there will be in his members no law warring against the law of his mind.^[1] But wholly will he love God, with all his heart, with all his soul and with all his mind,^[2] which is the first and chief commandment.

The number three has an intrinsic relation to the mind. This may be understood from the text in which we are commanded to love God in a threefold manner, with the whole heart, with the whole soul, with the whole mind.

Therefore the supreme and true wisdom is in that first commandment: You shall love the Lord your God with your whole heart and with your whole soul. From this it follows that wisdom is love of God, which is poured forth in our hearts, not otherwise than by the Holy Spirit who is given to us.^[1] But the fear of the Lord is the beginning of wisdom,^[2] and there is no fear in love, but perfect love casts out fear.^[3]

As the law teaches, You shall love the Lord your God with your whole heart and your whole soul. But the person who puts his entire hope in the Lord also praises with his whole heart. He does not put his trust in the transient consolations of the world, once he has trained himself on the Lord with total purity of mind.

What do you think, beloved? Didn’t Moses know beforehand that this would happen? Undoubtedly he did; but he acted thus, that there might be no sedition in Israel, and that the name of the true and only God might be glorified; to whom be glory forever and ever. Amen.

There will be no other God, Trypho, nor was there from eternity any other . . . but he who made this universe. Nor do we think that there is one God for us and another for you, but that he alone is God who led your fathers out of Egypt with a strong hand and a high arm. Nor have we trusted in any other, for there is no other, but him, in whom you also have trusted, the God of Abraham, and of Isaac, and of Jacob.

The Church, though dispersed throughout the whole world, even to the ends of the earth, has received from the apostles and their disciples this faith: [She believes] in one God, the Father Almighty, maker of heaven, and earth, and the sea, and all things that are in them; and in one Christ Jesus, the Son of God.

Nothing was either above him or after him; nor was he influenced by anyone, but of his own free will he created all things, since he is the only God, the only Lord, the only Creator, the only Father, alone containing all things, and himself commanding all things into existence.

The object of our worship is the one God, who, by the word of his command, by the reason of his plan, and by the strength of his power has brought forth from nothing this whole construction of elements, bodies, and spirits for the glory of his majesty; which is why the Greeks have bestowed upon the world the name “cosmos”.

[T]here is only one God, and he is none other than the Creator of the world, who produced all things out of nothing through his own Word, first of all sent forth.

We do indeed believe that there is only one God, but we believe that under this dispensation, or, as we say, “divine economy,” there is also a Son of this one and only God, his Word, who proceeded from him and through whom all things were made and without whom nothing was made.

The specific points that are clearly handed down through the apostolic preaching are these: First, that there is one God who created and arranged all things, and who, when nothing existed, called all things into existence, and that in the final period this God, just as he had promised through the prophets, sent the Lord Jesus Christ. . . . Secondly, that Jesus Christ himself, who came, was born of the Father before all creatures; and after he had ministered to the Father in the creation of all things. . . . Then, thirdly, the apostles related that the Holy Spirit was associated in honour and dignity with the Father and the Son.

The one God, the first and only, both Creator and Lord of all things, had nothing co-eternal. . . . No, he was one, to himself alone. And when he so willed, he created those things that before had no existence other than in his will to make them and in so far as he had knowledge of what would be, for he also has foreknowledge.

Thus God the Father, the founder and Creator of all things, who knows no beginning, invisible, infinite, immortal, eternal, is one God; to whose greatness, or majesty, or power nothing can be compared; of whom, when he willed it, the Son, the Word, was born. . . . [H]e then, since he was begotten of the Father, is always in the Father. And I thus say that I may show him not to be unborn, but born. But he who is before all time must be said to have been always in the Father; for no time can be assigned to him who is before all time %. And he is always in the Father, unless the Father be not always Father, only that the Father also precedes him, in a certain sense, since it is necessary—in some degree—that he should be before he is Father.

We therefore acknowledge one true God, the one first cause, and one Son, very God of very God, possessing by nature the Father’s divinity—that is to say, being the same in substance with the Father; and one Holy Spirit, who by nature and in truth sanctifies all, and makes divine, as being also of the substance of God. Those who speak either of the Son or of the Holy Spirit as a creature we anathematize.

There is one God. . . . There is a perfect Trinity, in glory and eternity and sovereignty, neither divided nor estranged. Therefore there is nothing either created or in servitude in the Trinity; or anything added on, as if at some former period it was nonexistent, and at some later period it was introduced. And thus neither was the Son ever wanting to the Father, nor the Spirit to the Son; but the same Trinity abides ever without variation and without change.

[T]he Scripture says, “As I live, says the Lord, there is no other God but me. I am the first, I am after this; except me there is no god” [Is 44:6]. And again: “You shall fear the Lord your God, and him only shall you serve” [Dt 6:13; Mt 4:10]. And again: “Hear, O Israel, the Lord your God is one Lord” [Dt 6:4]. And many other passages seal with an oath that God is one, and except him there is no God.

We believe in one God, the Father Almighty, maker of all things visible and invisible.

There is then one God and Father, and not two or three; one who is, and there is no other besides him, the only true [God]. For “the Lord your God,” says [the Scripture], “is one Lord” [Dt 6:4]. . . . And there is also one Son, God the Word. . . . And there is also one Paraclete.

[T]here is no other God, nor has there been before now, nor will there be hereafter, except God the Father unbegotten, without beginning, from whom is all beginning, upholding all things, and his Son Jesus Christ, whom we also confess to have been with the Father always—before the world’s beginning. . . . Jesus Christ is the Lord and God in whom we believe . . . and who has poured out the Holy Spirit on us abundantly . . . whom we confess and adore as one God in the Trinity of the sacred name.

True religion consists in the service of the one true God. That God is one, is truth itself. And just as without that one truth there is no other truth, so also without the one true God there is no other true God. For that one truth is one divinity. And so we cannot say that there are two true gods, just as truth cannot be divided.

What is to be said of justice in its relation to God? As the Lord says, No man can serve two masters,^[1] and the apostle rebukes those who serve the creature rather than the Creator,^[2] so had it not been said before in the Old Testament: You shall adore the Lord your God and him only shall you serve? But what need is there to say more about this here since the Scriptures are full of such texts? Justice then offers this rule of life to the lover we are describing: that he serve with gladness the Lord whom he loves, that is to say, the supreme good, the supreme wisdom, the supreme peace; and with respect to all other things, that he govern those which are subject to him and endeavor to subject all else to the same rule. This rule of life is confirmed, as we have shown, by the authority of both Testaments.

Whoever yields assent to the supreme authority of divine Scripture should first examine these words: The Lord your God shall you adore, and him only shall you serve. In Greek the expression used does not signify the service owed to human masters but that which is offered to God, called latreia. Thus idolatry is rightly condemned because the latreia which is due to the true God alone is offered to idols.^[1] It does not say, You shall adore only the Lord your God, but it says, And him only shall you serve. It used the word only with you shall serve, meaning, no doubt, that service which is called latreia. To this service belong temple, sacrifice, priest, and other like attributes.

[T]he Scripture says, “As I live, says the Lord, there is no other God but me. I am the first, I am after this; except me there is no god” [Is 44:6]. And again: “You shall fear the Lord your God, and him only shall you serve” [Dt 6:13; Mt 4:10]. And again: “Hear, O Israel, the Lord your God is one Lord” [Dt 6:4]. And many other passages seal with an oath that God is one, and except him there is no God.

These are the seven nations whose lands the Lord promised to give to the children of Israel when they left Egypt. We must accept the fact that, according to the apostle, all the things that happened to them in a figure were written for our instruction. . . .^[1] The reason that they are said to be much more numerous^[2] is that there are more vices than virtues. Therefore in the list they are counted as seven nations, to be sure, but when it is a question of destroying them they are said to be innumerable.

When you have received lawful authority, do all this.^[1] Where authority has not been given to us, we don’t do it; where it has been given, we don’t fail to do it. Many pagans have these abominations on their estates. Do we march in and smash them? The first thing we try to do is to break the idols in their hearts. When they too become Christians, they either invite us in to perform this good work or else they get in first with it before us. The thing we have to do now is pray for them, not get angry with them.