Considering the number of sins, he sees that he is incapable of himself
alone to make satisfaction for such grave evils; and so he is anxious to seek
out the assistance of the whole people.
Catechism of the Council of Trent (1566)
This Catechism referred to canonical penances and works of satisfaction,
but made no specific reference to Indulgences as. The question of
Indulgences was dealt with by the Council itself in its Decree Concerning
Indulgences, Session XXV, December 4, 1563:
Since the power of conferring indulgences was granted by Christ to
the Church; and she has, even in the most ancient times, used the
said power, delivered unto her by God: the holy synod teaches and
enjoins that the use of indulgencesmost salutary for the Christian
people, and approved of by the authority of sacred councilsis to be
retained in the Church; and it condemns with anathema those who
either assert that they are useless, or who deny that there is in the
Church the power of granting them.
Catechism of the Catholic Church (1992)
No. 1472:
To understand this doctrine and practice of the Church, it is
necessary to understand that sin has a double consequence. Grave sin
deprives us of communion with God and therefore makes us incapable of
eternal life, the privation of which is called the eternal punishment of sin.
On the other hand every sin, even venial, entails an unhealthy attachment to
creatures, which must be purified either here on earth, or after death in the
state called Purgatory. This purification frees one from what is called the
temporal punishment of sin.
No. 1478:
An indulgence is obtained through the Church who, by
virtue of the power of binding and loosing granted her by Christ Jesus,
intervenes in favor of individual Christians and opens for them the treasury
of the merits of Christ and the saints to obtain from the Father of mercies
the remission of the temporal punishments due for their sins. Thus the
Church does not want simply to come to the aid of these Christians, but
also to spur them to works of devotion, penance, and charity.