This is part 2 of a continuing series on why Luther was wrong. Pope Leo X declared the "Errors of Luther" in his papal bull, "Exsurge Domini" and this series examines those errors. This section deals with Luther's errors on the Sacrament of Penance.
11. By no means can you have reassurance of being absolved because of your contrition, but because of the word of Christ: "Whatsoever you shall loose, etc." Hence, I say, trust confidently, if you have obtained the absolution of the priest, and firmly believe yourself to have been absolved, and you will truly be absolved, whatever there may be of contrition.
The Act of Contrition is an important part of the Sacrament of Penance (aka, the Sacrament of Reconciliation). Contrition demonstrates one's true sorrow for the sins they committed. If one was not sincere in asking for forgiveness, then God will not forgive him those sins. A false confession is truly no confession.
12. If through an impossibility he who confessed was not contrite, or the priest did not absolve seriously, but in a jocose manner, if nevertheless he believes that he has been absolved, he is most truly absolved.
If this were true, then the person believing becomes the priest/minister of the Sacrament, and that is not the way Jesus Christ established the Sacrament of Penance/Reconciliation for us! He breathed upon them, the Apostles - our first bishops, and said "Those sins you shall forgive, are forgiven; those sins you to not forgive, they are not forgiven." This authority was specifically given to the bishopric - and remains with it to this day! Outside of one whom has been empowered by his bishop to forgive sins - sins are not forgiven. (A wake-up call for Protestants!)
13. In the sacrament of penance and the remission of sin the pope or the bishop does no more than the lowest priest; indeed, where there is no priest, any Christian, even if a woman or child, may equally do as much.
As stated in my response to #12, that authority to forgive sins is NOT granted to "even a woman or child" - but ONLY through the bishops and whom they have granted faculties to minister the Sacrament of Penance. That beings said, Luther's error here starts with a truism - what the pope or the bishop may do in relation to the Sacrament of Penance, is no more than the lowest priest who has been validly authorized. His conclusion is a non sequitur, it does not follow that in the absence of a priest that anyone can forgive sins.
14. No one ought to answer a priest that he is contrite, nor should the priest inquire.
Without the priest's knowledge of the contrition of the penitent, he could not, or at least should not, give absolution. If absolution is not given, the sins are not forgiven (no matter what the penitent "believes").