153 Q. Are actual sins ever remitted by Baptism? A. Actual sins and all the punishment due to them are remitted by Baptism, if the person baptized be guilty of any.
We know that Baptism remits Original Sin. But suppose a person is not baptized till he is twenty-five or thirty years old; he has surely committed some sins since he was seven years of age—the time at which he received the use of reason. Now the question asks, Are all his sins, those he committed himself as well as the Original Sin, forgiven by Baptism? The answer is, Yes. All his sins are forgiven, so that he has not to confess them. But he must be heartily sorry for them and have the firm determination of never committing them again, just as in confession. Moreover, that he may not have to confess these sins, we must be absolutely certain that he was never baptized before. Besides remitting the sins themselves, Baptism remits all the temporal punishment due to them.
In the Sacrament of Penance the sinner is saved from the eternal punishment—that is, Hell—and from part of the temporal punishment. But although the sins have been forgiven, the sinner must make satisfaction to God for the insult offered by his sins.
Therefore, he must suffer punishment in this world or in Purgatory. We call this punishment temporal, because it will not last forever. You can make this satisfaction to God while on earth, and thus avoid much of the temporal punishment by prayers, fasting, gaining indulgences, alms, and good works; and even by bearing your sufferings, trials, and afflictions patiently, and offering them up to God in satisfaction for your sins.
In Baptism both the eternal and temporal debt are washed away; so that if a person just baptized died immediately, he would go directly to Heaven, not to Purgatory: because persons go to Purgatory to pay off the temporal debt. Neither could that person gain an indulgence, because indulgences are only to help us to pay the temporal debt. Neither could that person receive the Sacrament of Penance, because Penance remits only sin committed after Baptism, and that person had no sins to remit, because he died just after receiving Baptism. See, then, the goodness of Our Lord in instituting Baptism, to forgive everything and leave us as free from guilt as our first parents were when God created them.