S. AURELII AUGUSTINI HIPPONENSIS EPISCOPI IN EPISTOLAM JOANNIS AD PARTHOS TRACTATUS DECEM .
TRACTATUS III. De eo quod sequitur, Pueri, novissima hora est usque ad id, Cap.
TRACTATUS IV. De eo quod sequitur, Et verax est, et non est mendax usque ad id, Cap. et cap.
TRACTATUS V. In id quod sequitur, Omnis qui natus est ex Deo, non facit peccatum usque ad id, Cap.
TRACTATUS VI. In illud, Et in hoc cognoscimus quia ex veritate sumus usque ad id, etc. Cap. et cap.
TRACTATUS VII. Ab eo quod sequitur, Jam vos ex Deo estis filioli usque ad id, Cap.
TRACTATUS VIII. De eo quod sequitur, Si diligamus invicem, Deus in nobis manebit usque ad id, Cap.
TRACTATUS IX. De eo quod sequitur, In hoc perfecta est dilectio in nobis usque ad id, Cap.
10. “Dearly beloved, I write unto you no new commandment, but the old commandment which ye had from the beginning.”55 1 John ii. 7. What commandment calls he “old? Which ye had,” saith he, “from the beginning. Old” then, in this regard, that ye have already heard it: otherwise he will contradict the Lord, where He saith, “A new commandment give I unto you, that ye love one another.”56 John xiii. 34. But why an “old” commandment? Not as pertaining to the old man. But why? “Which ye had from the beginning. The old commandment is the word which ye have heard.” Old then, in this regard, that ye have already heard it. And the selfsame he showeth to be new, saying, “Again, a new commandment write I unto you.”57 1 John ii. 8. Not another, but the selfsame which he hath called old, the same is also new. Why? “Which thing is true in Him and in you.” Why old, ye have already heard: i.e., because ye knew it already. But why new? “Because the darkness is past, and the true light now shineth.” Lo, whence it is new: because the darkness pertains to the old man, but the light to the new man. What saith the Apostle Paul? “Put ye off the old man, and put ye on the new.” 58 Col. iii. 9, 10. And again what saith he? “Ye were sometime darkness, but now light in the Lord.”59 Eph. v. 8.
10. Dilectissimi, non mandatum novum scribo vobis, sed mandatum vetus quod habebatis ab initio. Quod mandatum vetus dixit? Quod habebatis, inquit, ab initio. Ideo ergo vetus, quia jam illud audistis: alioquin contrarius erit Domino, ubi ait, Mandatum novum do vobis, ut vos invicem diligatis. Sed mandatum vetus quare? Non quia ad veterem hominem pertinet. Sed quare? Quod habebatis ab initio. Mandatum vetus, est verbum quod audistis. Ideo ergo vetus, quia jam audistis. Et idipsum novum ostendit dicens, Iterum mandatum novum scribo vobis. Non alterum, sed idem ipsum quod dixit vetus, idem est et novum. Quare? Quod est verum in ipso et in vobis. Jam quare vetus, audistis; quia jam illud noveratis. Quare autem novum? Quia tenebrae transierunt, et lux vera jam lucet. Ecce unde novum: quia tenebrae ad veterem hominem, lux vero ad novum pertinet. Quid dicit apostolus Paulus? Exuite vos veterem hominem, et induite novum (Coloss. III, 9, 10). Et iterum quid dicit? Fuistis aliquando tenebrae; nunc autem lux in Domino (Ephes. V, 8).