S. AURELII AUGUSTINI HIPPONENSIS EPISCOPI CONTRA MENDACIUM AD CONSENTIUM LIBER UNUS .
13. Or haply is it so, that he who plots in this way to find out Priscillianists, denies not Christ, forasmuch as with his mouth he utters what with his heart he believes not? As if truly (which I also said a little above) when it was said, “With the heart man believeth unto righteousness,” it was added to no purpose, “with the mouth confession is made unto salvation?”15 Rom. x. 10 Is it not so that almost all who have denied Christ before the persecutors, held in their heart what they believed of Him? And yet, by not confessing with the mouth unto salvation, they perished, save they which through penitence have lived again? Who can be so vain,16 Evanescat as to think that the Apostle Peter had that in his heart which he had on his lips when he denied Christ? Surely in that denial he held the truth within and uttered the lie without. Why then did he wash away with tears the denial which he uttered with his mouth, if that sufficed for salvation that with the heart he believed? Why, speaking the truth in his heart, did he punish with so bitter weeping the lie which he brought forth with his mouth, unless because he saw it to be a great and deadly evil, that while with his heart he believed unto righteousness, with his mouth he made not confession unto salvation?
13. An forte qui eo modo Priscillianistas invenire molitur, ideo non negat Christum, quia ore depromit quod corde non credit? Quasi vero (quod et paulo ante jam dixi) cum dictum esset, Corde creditur ad justitiam; incassum est additum, ore confessio fit ad salutem (Rom. X, 10)? Nonne pene omnes qui Christum coram persecutoribus negaverunt, quod de illo credebant, corde tenuerunt; et tamen ore ad salutem non confitendo perierunt, nisi qui per poenitentiam revixerunt? Quis ita evanescat , ut existimet apostolum Petrum hoc habuisse in corde quod in ore, quando Christum negavit? Nempe in illa negatione intus veritatem tenebat, et foris mendacium proferebat. Cur ergo lacrymis diluit quod ore negaverat (Matth. XXVI, 69-75), si saluti sufficiebat quod corde credebat? cur loquens in corde suo veritatem, tam amaro fletu punivit mendacium quod ore deprompsit, nisi quia magnam vidit esse perniciem, quod corde quidem credidit ad justitiam, sed ore non confessus est ad salutem?