As to Indulgences. The power to forgive sins necessarily included the power to remit the eternal punishment due to them. But there remains temporal punishment. But besides the power to forgive sins and their eternal punishment Christ also gave his Church the power to remit temporal punishment for sins.
In the remission of temporal punishment, that is, in indulgences, it is not a matter of regaining the state of grace, or of the essential goods of the supernatural order which we receive in the sacraments and through the objective effects of the sacraments ex opere operato (i.e. independently of one's own or the Church's merits but solely by the power of Christ working in the sacramental signs), but of a lessening of the punishments still due for sin. This remission comes about on the basis of the value as satisfaction of the works and sufferings of Christ and of all who can accomplish such works in the grace of Christ, i.e. of all persons in a state of grace. The application of this satisfying value, however, is not attached to any sacramental sign in itself but to certain actions which can be prescribed by the Church. Thus, the twofold basis of the doctrine of indulgences is: first, the satisfying and supernaturally meritorious value of all works done in a state of grace, and second, the community of saints, of all, that is, who have been redeemed by Christ and live and work in his grace, in communion with Christ and with one another.
Since the gaining of indulgences is related to certain actions, great abuses and scandals have been possible. The in part very abusive practice in matter of indulgences at the end of the Middle Ages served the Reformers as a symbol of a mechanistic organization of supernatural life, of the worldly character and avarice of the Church who touted holy things in the market-place. Against the, the Church declared her power to grant indulgences, and their value for the faithful, but at the same time she pull all her force into the campaign against abuses.
THE CHURCH THUS TEACHES
The Church, then, teaches she has received from Christ, on the basis of the treasury of his merits, the power to grant to the faithful on certain conditions indulgences i.e. the remission of temporal punishment due to sin. Indulgences may be applied to the dead. Abuses are to be avoided. The use of indulgences is salutary for the people of Christ.