Thomas Aquinas

“ It would not be right to avoid scandal so as to desert justice: for the truth should not be gainsayed for fear of scandal. Wherefore when justice and truth are in the balance, a man should not be deterred by the fear of giving scandal, from divulging what he has heard in confession, provided he knows it from some other source: although he ought to avoid giving scandal, as far as he is able. ”

“ Now it happens sometimes that a man by hiding a sin injures his own conscience---for instance, if he be called upon to give witness of a sin of which he has knowledge through confession, and is forced to swear to tell the truth---or when an abbot knows through confession the sin of a prior who is subject to him, which sin would be an occasion of ruin to the latter, if he suffers him to retain his priorship, wherefore he is bound to deprive him of the dignity of his pastoral charge, and yet in depriving him he seem to divulge the secret of confession. ”

“ Some say that the priest is not bound by the seal of confession to hide other sins than those in respect of which the penitent promises amendment; otherwise he may reveal them to one who can be a help and not a hindrance. But this opinion seems erroneous, since it is contrary to the truth of the sacrament; for just as, though the person baptized be insincere, yet his Baptism is a sacrament, and there is no change in the essentials of the sacrament on that account, so confession does not cease to be sacramental although he that confesses, does not purpose amendment. ”