Augustine of Hippo

“But if a soul should sin or hear the utterance of an oath, and he himself is a witness or sees or knows about it: if he does not make it known, he too will incur sin.” That is, “If he does not make it known, he will incur sin.” The addition of “and” is a common expression in the Scriptures. But this particular meaning, since it is obscure, seems to need an explanation. For it seems to say that a man sins when someone swears falsely in his hearing and he knows that that man is swearing falsely and remains silent. He knows this, if he was a witness to this matter about which an oath was taken, either having seen it or having known about it. That is, in some way he knows it. Either he saw it with his own eyes or the one who swears told him. For thus he could be aware of it. But between fear of this sin and fear of the treachery of men, there often arises no small temptation. For we can call someone back who is prepared to perjure himself by admonishing him or by preventing him from committing so grave a sin. If, however, he does not listen, and he swears in front of us about something that we know is false, a different question arises: should he be exposed—even if, once he is exposed, he comes into danger of death? But Scripture does not say here to whom this wrong should be made known—whether to the one to whom he swears, or to a priest or to someone who not only is unable to proceed against him by imposing a punishment but can even pray for him. It seems to me that one would free oneself even from the bond of sin if he reveals the fact to those who are able to help the perjurer rather than harm him, either by correcting him or by praying to God for him, if he himself uses the remedy of confession.