Chapter 16.—Origin of Errors; A Simile Sought from the Foreskin of the Circumcised, and from the Chaff of Wheat. “But surely,” say they, “if baptism cleanses the primeval sin, they who are born of two bap tized parents ought to be free from this sin; for these could not have transmitted to their children that thing which they did not themselves possess.” Now observe whence error usually thrives: it is when persons are able to start subjects which they are not able to understand. For before what audience, and in what words, can I explain how it is that sinful mortal beginnings bring no obstacle to those who have inaugurated other, immortal, beginnings, and at the same time prove an obstacle to those whom those very persons, against whom it was not an obstacle, have begotten out of the self-same sinful beginnings? How can a man understand these things, whose labouring mind is impeded both by its own prejudiced opinions and by the chain of its own stolid obstinacy? If indeed I had undertaken my cause in opposition to those who either altogether forbid the baptism of infants, or else contend that it is superfluous to baptize them alleging that as they are born of believing parents, they must needs enjoy the merit of their parents; then it would have been my duty to have roused myself perhaps to greater labour and effort for the purpose of refuting their opinion. In that case, if I encountered a difficulty before obtuse and contentious men in refuting error and inculcating truth, owing to the obscurity which besets the nature of the subject, I should probably resort to such illustrations as were palpable and at hand; and I should in my turn ask them some questions,—how, for instance, if they were puzzled to know in what way sin, after being cleansed by baptism, still remained in those who were begotten of baptized parents, they would explain how it is that the foreskin, after being removed by circumcision, should still remain in the sons of the circumcised? or again, how it happens that the chaff which is winnowed off so carefully by human labour still keeps its place in the grain which springs from the winnowed wheat?