Leviticus 19:18

Then, turning to His disciples, He says: “Woe unto him through whom offences come! It were better for him if he had not been born, or if a millstone were hanged about his neck and he were cast into the sea, than that he should offend one of these little ones,” that is, one of His disciples. Judge, then, what the sort of punishment is which He so severely threatens. For it is no stranger who is to avenge the offence done to His disciples. Recognise also in Him the Judge, and one too, who expresses Himself on the safety of His followers with the same tenderness as that which the Creator long ago exhibited: “He that toucheth you toucheth the apple of my eye.” Such identity of care proceeds from one and the same Being. A trespassing brother He will have rebuked. …

Furthermore, since both circumcision and uncircumcision were attributed to the same Deity, both lost their power in Christ, by reason of the excellency of faith, of that faith concerning which it had been written, “And in His name shall the Gentiles trust?”, of that faith “which,” he says “worketh by love.” By this saying he also shows that the Creator is the source of that grace. For whether he speaks of the love which is due to God, or that which is due to one’s neighbor, in either case, the Creator’s grace is meant: for it is He who enjoins the first in these words, “Thou shalt love God with all thine heart, and with all thy soul, and with all thy strength;” and also the second in another passage: “Thou shalt love thy neighbour as thyself.” “But he that troubleth you shall have to bear judgment.” From what God? From (Marcion’s) most excellent god? But he does not execute judgment. …

If the Father “sent His Son in the likeness of sinful flesh,” it must not therefore be said that the flesh which He seemed to have was but a phantom. For he in a previous verse ascribed sin to the flesh, and made it out to be “the law of sin dwelling in his members,” and “warring against the law of the mind.” On this account, therefore, (does he mean to say that) the Son was sent in the likeness of sinful flesh, that He might redeem this sinful flesh by a like substance, even a fleshly one, which bare a resemblance to sinful flesh, although it was itself free from sin. Now this will be the very perfection of divine power to effect the salvation (of man) in a nature like his own. …

You must know that in the eye of perfect, that is, Christian, modesty, (carnal) desire of one’s self (on the part of others) is not only not to be desired, but even execrated, by you: first, because the study of making personal grace (which we know to be naturally the inviter of lust) a mean of pleasing does not spring from a sound conscience: why therefore excite toward yourself that evil (passion)? why invite (that) to which you profess yourself a stranger? secondly, because we ought not to open a way to temptations, which, by their instancy, sometimes achieve (a wickedness) which God expels from them who are His; (or,) at all events, put the spirit into a thorough tumult by (presenting) a stumbling-block (to it). …

5. What, then, is that, how execrable should it appear to you, which I have learnt with extreme anguish and grief of mind, to wit, that there are not wanting those who defile the temples of God, and the members sanctified after confession and made glorious, with a disgraceful and infamous concubinage, associating their beds promiscuously with women’s! In which, even if there be no pollution of their conscience, there is a great guilt in this very thing, that by their offence originate examples for the ruin of others. …

“Say not, I will avenge me of mine enemy; but wait for the Lord, that He may be thy help.” Also elsewhere: “To me belongeth vengeance; I will repay, saith the Lord.” Also in Zephaniah: “Wait on me, saith the Lord, in the day of my rising again to witness; because my judgment is to the congregations of the Gentiles, that I may take kings, and pour out upon them my anger.”

XXV . Let him use those tenths and first-fruits, which are given according to the command of God, as a man of God; as also let him dispense in a right manner the free-will offerings which are brought in on account of the poor, to the orphans, the widows, the afflicted, and strangers in distress, as having that God for the examiner of his accounts who has committed the disposition to him. Distribute to all those in want with righteousness, and yourselves use the things which belong to the Lord, but do not abuse them; eating of them, but not eating them all up by yourselves: communicate with those that are in want, and thereby show yourselves unblameable before God. …

XXIII . For He did not take away the law of nature, but confirmed it. For He that said in the law, “The Lord thy God is one Lord;” the same says in the Gospel, “That they might know Thee, the only true God.” And He that said, “Thou shalt love thy neighbour as thyself,” says in the Gospel, renewing the same precept, “A new commandment I give unto you, that ye love one another.” He who then forbade murder, does now forbid causeless anger. He that forbade adultery, does now forbid all unlawful lust. He that forbade stealing, now pronounces him most happy who supplies those that are in want out of his own labours. He that forbade hatred, now pronounces him blessed that loves his enemies. He that forbade revenge, now commands long-suffering; not as if just revenge were an unrighteous thing, but because long-suffering is more excellent. …

II . The first way, therefore, is that of life; and is this, which the law also does appoint: “To love the Lord God with all thy mind, and with all thy soul, who is the one and only God, besides whom there is no other;” “and thy neighbour as thyself.” And whatsoever thou wouldest not should be done to thee, that do not thou to another.” “Bless them that curse you; pray for them that despitefully use you.” “Love your enemies; for what thanks is it if ye love those that love you? for even the Gentiles do the same.” “But do ye love those that hate you, and ye shall have no enemy.” For says He, “Thou shalt not hate any man; no, not an Egyptian, nor an Edomite;” for they are all the workmanship of God. Avoid not the persons, but the sentiments, of the wicked. …

21. Neither ought any one to have joy in himself, if you look at the matter clearly, because no one ought to love even himself for his own sake, but for the sake of Him who is the true object of enjoyment. For a man is never in so good a state as when his whole life is a journey towards the unchangeable life, and his affections are entirely fixed upon that. If, however, he loves himself for his own sake, he does not look at himself in relation to God, but turns his mind in upon him self, and so is not occupied with anything that is unchangeable. And thus he does not enjoy himself at his best, because he is better when his mind is fully fixed upon, and his affections wrapped up in, the unchangeable good, than when he turns from that to enjoy even himself. …

9. But if no authority for lying can be alleged, neither from the ancient Books, be it because that is not a lie which is received to have been done or said in a figurative sense, or be it because good men are not challenged to imitate that which in bad men, beginning to amend, is praised in comparison with the worse; nor yet from the books of the New Testament, because Peter’s correction rather than his simulation, even as his tears rather than his denial, is what we must imitate: then, as to those examples which are fetched from common life, they assert much more confidently that there is no trust to be given to these. …

57. The Manichæans agree with me as regards the duty of loving God and our neighbor, but they deny that this is taught in the Old Testament. How greatly they err in this is, I think, clearly shown by the passages quoted above on both these duties. But, in a single word, and one which only stark madness can oppose, do they not see the unreasonableness of denying that these very two precepts which they commend are quoted by the Lord in the Gospel from the Old Testament, "Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind;" and the other, "Thou shalt love thy neighbor as thyself?" Or if they dare not deny this, from the light of truth being too strong for them, let them deny that these precepts are salutary; let them deny, if they can, that they teach the best morality; let them assert that it is not a duty to love God, or to love our neighbor; …