[Question:]{.underline} Can a person perform the penance received in Confession after having fallen back into mortal sin?
[Answer:]{.underline} The penance received in Confession ought to be performed as soon as possible after Confession, so that a person who delays for no reason the fulfillment of a heavy penance given for a mortal sin so as to be in danger of forgetting his penance, would commit another mortal sin.
It is true that it is not necessary that the penance be performed before going to Holy Communion, and that frequently there is no time to perform the penance before the opportunity of receiving Holy Communion presents itself. There is no reason why such a person ought not to receive the Blessed Sacrament.
However, the penance must be done before going back to Confession. If a person were unfortunate enough to lose the state of sanctifying grace before being able to do his penance, or through his own negligence, he would be in a difficult situation. It is probable that the penance performed in mortal sin does not have its full satisfactory value, which depends upon the union of charity between God and the soul, which union has been lost. Yet, the penitent in mortal sin is still bound to do the work of penance before going back to Confession. The common opinion of the theologians is that the penance done after falling back into mortal sin satisfies with respect to the work imposed by the Confessor, and that it consequently does not have to be reiterated after the person has gone back to Confession and recovered the state of grace (Prummer, Man. Th. Mor., III, §402). However, a person in such a situation ought to make an act of perfect contrition so as to recover the state of sanctifying grace before doing the penance in order that this work can not only fulfill the command of the priest but also have a real satisfactory value in making up for his sins.
[Question:]{.underline} Can a person perform the penance received in Confession after having fallen back into mortal sin?
[Answer:]{.underline} The penance received in Confession ought to be performed as soon as possible after Confession, so that a person who delays for no reason the fulfillment of a heavy penance given for a mortal sin so as to be in danger of forgetting his penance, would commit another mortal sin.
It is true that it is not necessary that the penance be performed before going to Holy Communion, and that frequently there is no time to perform the penance before the opportunity of receiving Holy Communion presents itself. There is no reason why such a person ought not to receive the Blessed Sacrament.
However, the penance must be done before going back to Confession. If a person were unfortunate enough to lose the state of sanctifying grace before being able to do his penance, or through his own negligence, he would be in a difficult situation. It is probable that the penance performed in mortal sin does not have its full satisfactory value, which depends upon the union of charity between God and the soul, which union has been lost. Yet, the penitent in mortal sin is still bound to do the work of penance before going back to Confession. The common opinion of the theologians is that the penance done after falling back into mortal sin satisfies with respect to the work imposed by the Confessor, and that it consequently does not have to be reiterated after the person has gone back to Confession and recovered the state of grace (Prummer, Man. Th. Mor., III, §402). However, a person in such a situation ought to make an act of perfect contrition so as to recover the state of sanctifying grace before doing the penance in order that this work can not only fulfill the command of the priest but also have a real satisfactory value in making up for his sins.
Answered by Father Peter Scott, SSPX.