What is it about purgatory that divides Catholics from Protestants? Does it actually have to do with justification? At first, I think it’s important to state that there is only so much that we can possibly know about purgatory—like Heaven or hell.
My post here will be mostly informal and written from my observations having spent a great deal of time and having a magnificent opportunity listening to confessional Lutherans. I’ve heard told in many circles that Martin Luther, a pious Christian, had been using the sacrament of confession; however, after each time of reconciliation, the Augustinian monk, would hesitate a bit while walking back to his theological studies as he just remembered sins that he forgot to confess. Luther, then, thought something of the nature, “I must still be damned.” The term for this is called scrupulosity, in fact, I was having a discussion on Justification and purgatory one night, I said, “I believe that at best, I will no doubt have to be purified in purgatory, I then used the term, scrupulosity, in response to being told, “I just want you to have peace.” I looked very puzzled at the reply, “peace?” The individual thought that there was no possible way that I could be confident in my salvation if I had to continue to worry about my sins and practice the sacrament of confession. However, my response, “I already have peace. I can be confident in both my state of grace and the mercy of God; however, If I do deserve damnation, I have faith in God’s true justice.”
So, why do I have confidence in the doctrine of purgatory, as opposed to this individual and Luther? There are various proofs in Scripture that Catholics point to in regards to Purgatory such as 1 Cor. 3:11-15, Jn. 14:2, Mt. 12:32.
However, my confidence rests on the words of Jesus Christ in Matthew Ch. 5:23-26
23 Therefore, if you bring your gift to the altar, and there recall that your brother has anything against you, 24 leave your gift there at the altar, go first and be reconciled with your brother, and then come and offer your gift. 25 Settle with your opponent quickly while on the way to court with him. Otherwise your opponent will hand you over to the judge, and the judge will hand you over to the guard, and you will be thrown into prison. 26 Amen, I say to you, you will not be released until you have paid the last penny. 
The great accuser—The opponent– that we will all have at our judgment is Satan. So, here are two topics that many Christians fail to speak about in this day and age, Satan and Sin, mainly because most no longer believe in either. So, if most do not believe that there are Satan and Sin, is it fair to say that it would be difficult to believe in a purification of Sin? Could one make the argument that our failure to acknowledge such is founded in Sola Fide? Perhaps not, after all, many Catholics no longer believe that Satan or Sin exists. In regards to on the way to court, of course, this means our life on the way to the beatific vision, and our way to settle our debt of sin is with confession and penance.
It’s important to note that Christ then says, “you will not be released until you have paid the last penny.” Christ couldn’t be talking about hell as the verdict from the Judge by this statement because if the judgment is hell, the judgment is final; however, purgatory is not a final state, but rather a purifying state, in which one will be “released;” therefore, their judgment of salvation has been assured.
One of the best pieces of Western Literature is Dante’s Divine Comedy, one of the great attributes of the text is that it speaks to us today of the Christian worldview of a faithful Catholic in the 13th century before the Reformation.
Notice, even in both Canto III’s of the Inferno and Purgatory the difference of the fates of those souls:
Here sighs, with lamentations and loud moans,
Resounded through the air pierced by no star,
That e’en I wept at entering. Various tongues,
Horrible languages, outcries of woe,
Accents of anger, voices deep and hoarse,
With hands together smote that swell’d the sounds,
Made up a tumult, that forever whirls
Round through that air with solid darkness stain’d,
Like to the sand that in the whirlwind flies.
I then, with horror yet encompast, cried:
“O master! what is this I hear? what race
Are these, who seem so overcome with woe?”
“O spirits perfect! O already chosen!”
Virgil to them began: “by that blest peace,
Which, as I deem, is for you all prepared,
Instruct us where the mountain low declines,
So that attempt to mount it be not vain.
For who knows most, him loss of time most grieves.”
In Dante’s Hell, those souls, as with every circle of hell, are continuously moved in endless unending circles, but notice, that in purgatory, as Virgil says as the souls approach him and Dante, “O already Chosen!” those spirits are beginning to move forward as pilgrims to the reward they’re already assured as they can not move back.
The Book of Concord reads in regards to penance in indulgence:
They add further that satisfactions ought to be works of supererogation. These consist of the most stupid observances, like pilgrimages, rosaries, and similar observations, none of which have the command of God.  Then, just as they buy off purgatory with satisfactions, so they also devised a way to buy off satisfactions, which turned out to be very profitable. For they sell indulgences, which they interpret as the remission of satisfactions. They collect this revenue not only from the living but even more from the dead. They buy off the satisfactions for the dead not only with indulgences but also with the sacrifice of the Mass.
As I read the above text, I hear the “voice” of the writer, in respect, to being angry at the selling for profit of indulgences in regards to removing penance. I fully admit that those in the Church, and yes even leaders, are sinners and did egregious actions. Regardless, Catholics and Protestants differ on how God conducts commands. Protestants claim Sola Scriptura while Catholics claim that Church tradition can also produce theological truths. However, after applying Christ words using scripture, can it truly be claimed there is no command from God? Furthermore, is it “works” to simply pray for souls in purgatory? It’s well noted in the historical record that Luther edited books from the canon that displayed prayers for the dead, as it opposed to his prospective theology. It’s clear from Catholic theology that souls who receive no prayers will still be purified and receive their reward, in this regard, no action from anyone is meriting salvation, as salvation is assured. God initiates by a free gift salvation. I implore my Protestant brothers and sisters to see that “works” is not a bad word. If salvation is granted to us Prima Gratia, Christ still speaks time and time again about “storing treasures in Heaven” by actions on earth.
 New American Bible, Revised Edition (Washington, DC: The United States Conference of Catholic Bishops, 2011), Mt 5:22–26.
 Dante Alighieri, The Harvard Classics 20: The Divine Comedy by Dante, ed. Charles W. Eliot (New York: P. F. Collier & Son, 1909), 13–14.
 Dante Alighieri, The Harvard Classics 20: The Divine Comedy by Dante, ed. Charles W. Eliot (New York: P. F. Collier & Son, 1909), 157.
Robert Kolb, Timothy J. Wengert, and Charles P. Arand, The Book of Concord: The Confessions of the Evangelical Lutheran Church (Minneapolis, MN: Fortress Press, 2000), 190.