On the words of the Gospel, John x.30, "I and the Father are one."
1. Ye have heard what the Lord God, Jesus Christ, the Only Son of God, born of God the Father without any mother, and born of a Virgin mother without any human father, said, "I and My Father are One."  Receive ye this, believe it in such wise that ye may attain  to understand it. For faith ought to go before understanding, that understanding may be the reward of faith. For the Prophet hath said most expressly, "Unless ye believe, ye shall not understand."  What then is simply preached is to be believed; what is with exactness discussed, is to be understood. At first then  to imbue your minds with faith we preach to you Christ, the Only Son of God the Father. Why is added, "The Only Son"? Because He whose Only Son He is, hath many sons by grace. All the rest then, all saints are sons of God by grace, He Alone by Nature. They who are sons of God by grace are not What the Father is. And no saint hath ever dared to say, what that Only Son saith, "I and My Father are One." Is He not then our Father too? If He be not our Father, how say we when we pray, "Our Father, which art in heaven"?  But we are sons whom He hath made sons by His Own will, not begotten as sons of His Own Nature. And in truth He hath begotten us too, but as it is said, as adopted ones, begotten by the favour of His adoption, not by Nature. And this too are we called, for that "God hath called us into the adoption of sons;"  we are though adopted, men. He is called the Only Son, the Only Begotten, in that, He is That which the Father is; but we are men, The Father is God. In then that He is That which the Father is; He said, and said truly, "I and My Father are One." What is, "are One"? Are of one Nature. What is, "are One"? Are of one Substance.
2. Peradventure, ye but imperfectly understand what "of one Substance" is. Take we pains that ye may understand it; may God assist both me who speak, and you that hear; me, that I may speak such things as are true and fit for you; and you, that before and above all things ye may believe; and then that ye may understand as best ye can. What then is "of One Substance"? Let me make use of similitudes to you, that what is imperfectly understood may be made clear by example. As, suppose, God is gold. His Son is gold also. If similitudes ought not to be given for heavenly things from things earthly, how is it written, "Now the Rock was Christ"?  So then, Whatsoever the Father is, This is the Son also; as I have said, for example, "The Father is gold, the Son is gold." For he who says, "The Son is not of the Very Substance which the Father is;" what else says he but, "The Father is gold, the Son is silver"? If the Father be gold, and the Son silver; the Only Son hath degenerated from the Father. A man begets a man; of what substance the father is who begets, of the same substance is the Son who is begotten. What is, "of the same substance"? The one is a man, and the other is a man; the one hath a soul; so hath the other a soul; the one hath a body, so hath the other a body; what one is, that is the other.
3. But the Arian heresy makes answer, and says. What says it to me? "Mark what thou hast said"? What have I said? "That the Son of a man may be compared to the Son of God." Certainly he may be compared; but not as you suppose, in strictness of expression;  but for a similitude. But tell me now what you would make of this. "Do you not see," says he, "that the father who begets is greater  in age, and the son who is begotten less? How then say ye? tell me; how then say ye, that the Father and the Son, God and Christ, are equal; when ye see that when a man begets a son, the son is less, and the father greater?" Thou wise one, in eternity thou art looking for times; where there are no times, thou art looking for differences of age! When the father is greater in age, and the son less, both are in time; the one groweth, for that the other groweth old. For by nature, the man, the father, did not beget one less, by nature, as I said, but by age. Wouldest thou know, how that by nature he did not beget one less? Wait, let him grow, and he will be equal to his father. For a little boy even by growing attains to his father's full size. Whereas you assert that the Son of God is in such wise born less, as never to grow, and by growing even to attain to His Father's size. Now then a man's son born of a man, is born in a better condition than the Son of God. How? Because the former grows, and attains to his father's size. But Christ, if it is as ye say, is in such wise born less, as that He must ever remain less, and no growth of years at least is to be looked for here. Thus then you say that there is a diversity in nature. But why say you so, but because you will not believe the Son to be of the Same Substance which the Father is? Finally, first acknowledge that He is of the Same Substance, and so call Him less. Consider the case of a man, he is a man. What is his substance? He is a man. What is he whom he begets? He is less, but he is a man. The age is unequal, the nature equal. Do you then say too, "What the Father is, That is the Son, but the Son is less"? Say so, make a step forward, say, "of the Same Substance, only less;" and you will get to His being equal. For it is not a little step you take, it is not a little approach you make to the truth, of acknowledging Him equal, if you shall acknowledge Him to be of the Same Substance, though less. "But He is not of the Same Substance," this you say. So then in that you say this, here is gold and silver; what you say is as if a man were to beget a horse. For a man is of one substance, a horse of another. If then the Son is of another substance than the Father, the Father hath begotten a monster. For when a creature, that is a woman, gives birth to anything that is not a man, it is called a monster. But that it be not a monster, he that is born is that which he is that begat him, that is, a man and a man, a horse and a horse, a dove and a dove, a sparrow and a sparrow.
4. To His creatures hath He given to beget that which they are. To His creatures, to mortal, earthly creatures, hath God given, hath granted to beget that which they are; and thinkest thou that He hath not been able to reserve this for Himself, He who is before all ages? Should He who hath no beginning of time, beget a son, different from That which Himself is, beget a degenerate son? Hear ye how great a blasphemy it is to say, that the Only Son of God is of another substance. Most certainly if He is so, He is degenerate. If you should say to any child of man, "Thou art degenerate," how great an offence is it! And yet in what sense is any child of man said to be degenerate? As, for example, his father is brave, he is a poltroon and a coward. If any one sees him, and would rebuke him, as he thinks of his brave father, what does he say to him? "Get thee hence, thou degenerate one!" What is "degenerate one"? "Thy father was a brave man, and thou tremblest through fear." He to whom this is said, is degenerate by some fault, by nature he is equal. What is, "by nature he is equal"? He is a man, which his father also is. But the one brave, the other a coward; the one bold, the other timid; yet both men. By some fault then he is degenerate, not by nature. But when you say, that the Only Son, the One Son of the Father, is degenerate, you say nought else, but that He is not What the Father is; and you do not say, that having been already born, He has become degenerate; but He was begotten so. Who can endure this blasphemy? If they could in any sort whatever see this blasphemy, they would fly from it, and become catholics.
5. But what shall I say, Brethren? Let us not be angry with them; but pray we for them, that God would give them understanding; for peradventure they were born so.  What is, were born so? They receive what they hold from their parents. They prefer their birth to the truth. Let them become what they are not, that they may be able to keep what they are; that is, let them become catholics, that they may keep their nature as men; that the creation of God in them perish not, let the grace of God be added to them. For they imagine that by their outrage of the Son they honour the Father. When you say to him, "Thou blasphemest;" he answers, "Why do I blaspheme?" "In that thou sayest that the Son is not what the Father is." And he answers me, "Yea, it is thou who blasphemest." Why? "Because thou wouldest make the Son equal to the Father." "I do wish to make the Son equal with the Father, but is this to make a stranger equal? The Father rejoiceth when I equal with Him His Only Son; He rejoiceth because He is not envious. And because God is not envious of His Only Son, therefore did He beget Him Such as He is Himself. Thou doest wrong both to the Son, and to the Father Himself, for whose honour thou wouldest do outrage to the Son. For in truth for this reason dost thou say that the Son is not of the Same Substance, lest thou shouldest do wrong to His Father. I will soon show thee, that thou doest wrong to both." "How?" saith he. "If I say to any man's son, Thou art degenerate, thou art not like thy father; degenerate, thou art not what thy father is. The son hears it, and is angry, and says, Was I then born degenerate?' The father hears it, and is more angry still. And in his anger what says he? Have I then begotten a degenerate son? If I then be one thing, and I have begotten another, I have begotten a monster.' What is it then, that whereas thou wishest to pay honour to the One by doing outrage to the Other, thou doest outrage to Both? Thou offendest the Son, but thou wilt not propitiate the Father. When thou honourest the Father by outraging the Son, thou offendest both the Son and the Father. From whom wilt thou fly? to whom wilt thou fly? When the Father is angry with thee, dost thou fly to the Son? What doth He say to thee? To whom dost thou fly, to Me, whom thou hast made degenerate?' When the Son is offended, dost thou run to the Father? He too saith to thee; To whom dost thou fly, to Me who, thou hast said, have begotten a degenerate Son?'" Let this suffice for you; hold it fast, commit it to memory, inscribe it in your faith. But that ye may understand it, pour out your prayers to God, the Father and the Son, who are One.
 John 10:30.  Mereamini.  Isaiah 7:9, Sept.  He seems to be addressing the Catechumens (Bened. note).  Matthew 6:9.  Ephesians 1:5.  1 Corinthians 10:4.  Ad proprietatem.  Major.  Arians.
 Isaiah 7:9, Sept.
 He seems to be addressing the Catechumens (Bened. note).
 Matthew 6:9.
 Ephesians 1:5.
 1 Corinthians 10:4.
 Ad proprietatem.