If I understand it correctly, an indulgence is a prepaid get-out-of-jail free card for one or more future sins.
If my understanding is correct, then an Indulgence cheapens the purpose of holy living.
In reality, 1 John 1 + 1 John 2 make it clear we continue to sin and if we can confess that then we are cleansed by Jesus.
I would be extremely reluctant to let go of that promise.
No.
"If I understand correctly, an indulgence is a prepaid 1
get-out-of-jail free card 2
...for one or more future sins3.
[So] Indulgence cheapens the purpose of holy living4.
In reality, 1 John 1 + 2 make it clear we continue to sin and if we can confess that then we are cleansed by Jesus. 5
I would be extremely reluctant to let go of that promise. 6
1. This was in fact a flagrant money-making biz for instance when St. Peter's Basilica was being built. But that's an abuse. It is, and always has been, a sin to exchange any sort of spiritual goods for money --- the sin of simony --- and those who did this (Pope Leo X together with his notorious "salesmen" like Johann Tetzel) were rightly rebuked at the time, and to this day are regarded as early-Renaissance scoundrels, not as saints.
In other words, what you are objecting to in this case, was not the use, but the abuse of indulgences.
2. An indulgence is not about get-out-of-jail-free, but a way to help each other by prayers and charitable practices, and as a kind of spiritual repair work. Briefly, the ancient, and more severe ecclesiastical penalties (such as months or years of public penance for a grave sin -- armed robbery, murder, sodomy, apostasy) were replaced with much more lenient acts of devotion (like going on a pilgrimage, repairing a church, supporting orphans.) This is not for the forgiveness of past sins. This is for sins that have already been repented, confessed and forgiven.
3. Indulgences have nothing to do with future sins. Repentance and God's forgiveness are preconditions for indulgences, since you can't repent of something you're going to do in the future, and you can't receive any sort of spiritual good unless you is in a state of sanctifying grace. All of this is Christ's work on the Cross. All of this is guaranteed to the repentant sinner, who receives forgiveness and grace as a gift, just as the "Good Thief" did. Eternal punishment has been completely washed away by the blood of Christ crucified.
4. Gaining an indulgence actually manifests a commitment to holy living. It is balancing the scales of justice after forgiveness by being an outward sign of one's inward change of mind (metanoia) and doing good to repair the harm you've done (e.g. charitable work to repair one's previous works of avarice.)
It repairs temporal damage and remits temporal punishment. Again, this is only an analogy, but it's like an apology, a statement of remorse and a stint of community service instead of jail.
Matthew 3:8
Bear fruit worthy of repentance.
4. To use an analogy to human justice, we understand that one who has been forgiven must still "pay a debt to society." If a couple of teens got drunk, started tossing lighted matches here and there and burned down a forest, even if they're forgiven, maybe they should give $10,000 to the National Park Service? Give 100 talks at schools against drunkenness and playing with fire? Plant 100,000 trees?
5. This is not letting go of God's promise of forgiveness. It is part of acknowledging the harm done by one's sins, the justice of God's punishments, and the reality of one's change of heart.
Acts 26:20
First to those in Damascus and Jerusalem, then to everyone in the region of Judea, and then to the Gentiles, I declared that they should repent and turn to God, performing deeds worthy of their repentance.