So what’s the ‘treasury of the church’ thing? Is that like a metaphysical bank of good that I can add to? (I’m not being flippant; I’m really trying to understand this. Thanks for your help!)
The treasury of the Church is the satisfactory merits of the saints and Jesus Christ… these merits are superabundant, that is, more than sufficient, and so, they can be applied to others.
Every time you commit a sin there’s a certain amount of penance or temporal
punishment as a penalty due to it for the sake of Justice. Either you do the penance or someone else does it for you. Indulgences are someone else doing it for you – or, if you gain them for someone in purgatory, someone in purgatory who cannot gain them on his own.
“Each good action of the just man possesses a double value: that of merit and that of satisfaction, or expiation. Merit is personal, and therefore it cannot be transferred; but satisfaction can be applied to others, as St. Paul writes to the Colossians (1:24) of his own works: “Who now rejoice in my sufferings for you, and fill up those things that are wanting of the sufferings of Christ, in my flesh, for his body, which is the Church.””
. . . Since the satisfaction of Christ is infinite, it constitutes an inexhaustible fund which is more than sufficient to cover the indebtedness contracted by sin, Besides, there are the satisfactory works of the Blessed Virgin Mary undiminished by any penalty due to sin, and the virtues, penances, and sufferings of the saints vastly exceeding any temporal punishment which these servants of God might have incurred.
- The Catholic Encyclopedia
Indulgences used to have equivalent values to earthly penances given to them, such as a pilgrimage of 100 days, etc. Now they are partial or plenary only, thanks to Pope Paul VI, and each partial indulgence is worth only again as much as you put into the work itself.
How easy it is to gain a plenary indulgence is debated. Some believe it is very very hard, others somewhat less so.
