
In a recent post on his blog, Hiram Diaz, claims that Holy Mother Church's belief in such makes her claim of being the church founded by Christ a falsehood. According to the subtitle of his post it is a scriptural refutation; however in all of his bullet points I see only one mention of scripture (Jer. 31:34

I like this particular verse which says in effect that God will forgive us all of our sins and remember them no more. However in no way does this refute Purgatory nor Roman Catholicism. It seems to me that to disbelieve in the overwhelming scriptural evidence that would seem to support Purgatory is an attempt to deny God's eternal mercy.
First let's unpack that verse from Jeremiah and show how it in no way refutes Purgatory. The idea of Purgatory is that it is intended to help cleanse a person from all attachments to sin, from love of self, so that when they enter Heaven they will have only love of God.
In 2 Sam. 12 we see the story of King David's affair with Uriah's wife. David confesses his sin to the prophet Nathan, who tells him The Lord has taken away your sin and you shall not die (2 Sam 12:13

We also see in 2 Maccabees that Judas Maccabeus offers prayers and sacrifices for the dead (2 Macc. 12:43-46

We also see Jesus mention this third state of post-Earthly life. Matthew 12:32

We also see in St. Luke's Gospel (Lk. 16:19-31

St. Paul's epistles also feature numerous references to the idea (such as 1 Cor. 3:10-15

It seems the flaw in Diaz's attempt to discredit Holy Mother Church comes from his poorly constructed straw man detailing what Purgatory is and is intended to accomplish.For as I have shown even scripture details that God can forgive us our sins, yet still require us to make reparations for them. Much like if a father loaned his son the car for the night and the son had an accident; the father might forgive the son for having the accident but still require him to pay for the repairs.
God is both boundless mercy and boundless justice. This is one of the many paradoxes of the faith that we must come to terms with. In His desire that all men shall be saved (1 Tim. 2:4


Finally let's take a look at St. Augustine's writings concerning the idea of Purgatory:
"For our part, we recognize that even in this life some punishments are purgatorial,--not, indeed, to those whose life is none the better, but rather the worse for them, but to those who are constrained by them to amend their life. All other punishments, whether temporal or eternal, inflicted as they are on every one by divine providence, are sent either on account of past sins, or of sins presently allowed in the life, or to exercise and reveal a man's graces. They may be inflicted by the instrumentality of bad men and angels as well as of the good. For even if any one suffers some hurt through another's wickedness or mistake, the man indeed sins whose ignorance or injustice does the harm; but God, who by His just though hidden judgment permits it to be done, sins not. But temporary punishments are suffered by some in this life only, by others after death, by others both now and then; but all of them before that last and strictest judgment. But of those who suffer temporary punishments after death, all are not doomed to those everlasting pains which are to follow that judgment; for to some, as we have already said, what is not remitted in this world is remitted in the next, that is, they are not punished with the eternal punishment of the world to come."
Augustine, City of God, 21:13 (A.D. 426).
"But since she has this certainty regarding no man, she prays for all her enemies who yet live in this world; and yet she is not heard in behalf of all. But she is heard in the case of those only who, though they oppose the Church, are yet predestinated to become her sons through her intercession...For some of the dead, indeed, the prayer of the Church or of pious individuals is heard; but it is for those who, having been regenerated in Christ, did not spend their life so wickedly that they can be judged unworthy of such compassion, nor so well that they can be considered to have no need of it. As also, after the resurrection, there will be some of the dead to whom, after they have endured the pains proper to the spirits of the dead, mercy shall be accorded, and acquittal from the punishment of the eternal fire. For were there not some whose sins, though not remitted in this life, shall be remitted in that which is to come, it could not be truly said, "They shall not be forgiven, neither in this world, neither in that which is to come.' But when the Judge of quick and dead has said, 'Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world,' and to those on the other side, 'Depart from me, ye cursed, into the eternal fire, which is prepared for the devil and his angels,' and 'These shall go away into eternal punishment, but the righteous into eternal life,' it were excessively presumptuous to say that the punishment of any of those whom God has said shall go away into eternal punishment shall not be eternal, and so bring either despair or doubt upon the corresponding promise of life eternal."
Augustine, City of God,2 1:24 (A.D. 426).