Chapter — Slater, Manual of Moral Theology
Chapter XIII. Mistakes made in Hearing Confessions
ONE who culpably causes unjust harm to another is bound in justice to repair that harm as far as he can. Even if the action which causes harm to another is done innocently, there will nevertheless arise an obligation to prevent the harm as far as possible as soon as the danger is noticed, and if there is grave negligence in doing this without reasonable excuse, injustice will be committed and the obligation of making restitution incurred. A confessor who admits a penitent to confession is bound in justice to absolve him if he is properly disposed for absolution. And so if he has neglected to do so, he must repair the error afterward, especially if the penitent were in danger of death and may die in sin without sacramental absolution.
Similarly, if the confessor gave his penitent false instruction in faith or morals, or bad advice, or bound him to make restitution when he was under no obligation to do so by the law of God, or released him from such an obligation when he was really under it, the confessor must afterward correct his mistake, taking the precaution to ask the penitent’s leave to say something to him about his confession if an opportunity is afforded him only out of confession. When the penitent was wrongfully compelled to make restitution with grave fault on the part of the confessor, the latter is bound in justice to make him restitution for the loss that he has suffered, if he cannot otherwise recover his money. The confessor is in the same way bound to make restitution to the defrauded creditor when, with grave fault, he released a penitent from the obligation of paying a just debt, if in consequence the penitent is now unwilling or unable to fulfil his obligation.
p. ii, 172
If the confessor merely neglected to impose a penance, or supply for the deficiency of the penitent’s confession by questioning him, or failed to correct some mistake that he was labouring under, or to warn him of the obligation of making restitution, he did not thereby sin against justice, and he is not bound to make restitution, unless indeed in the circumstances his silence was equivalent to positive approval. Still, if knowingly and wilfully he did any of these things, he committed sin, and in as far as harm to his penitent or to others ensued he violated charity, which obliges every man to do what he can to prevent loss and damage to others. Even out of confession if he can prevent harm being caused by his failure to do his duty in the confessional, he should with the penitent’s leave do his best to prevent it.
p. ii, 172–173