What we have said so far should reveal the falsity of this charge. Purgatory is in no way an unbiblical doctrine. Rather, it is completely biblical on both implicit and explicit grounds. Implicitly, it can be derived from the biblical principles that we still sin till death but that there will be no sin in glory. Thus between death and glorification must come purification.
Explicitly, we not only have the witness of passages such as 2 Maccabees 12, but also the witness of passages describing our accounting before Christ in the particular judgment, including the especially vivid depiction of one escaping through the flames in 1 Corinthians 3:11-15.
Jesus himself adds to this when he speaks in Matthew 12:32 of a sin which will neither be forgiven in this age nor the age to come, implying that some sins (venial ones of which we have not repented before death) will be forgiven when we repent the first moment of our afterlife.
Furthermore, in Matthew 5:25-26, Jesus tells us: “Make friends quickly with your accuser, while you are going with him to court, lest your accuser hand you over to the judge, and the judge to the guard, and you be put in prison; truly, I say to you, you will never get out till you have paid the last penny.”
In this parable God is the Judge, and if we have not reconciled with our neighbors before we see God, God will hold us accountable for the wrong we did to them. This is what the Bible means when it says that God will take our revenge for us, so we should not take it ourselves, because God will defend the cause of the poor and uphold the case of the widow. Whenever a poor person or widow (or anyone else) is oppressed or wronged, God will hold the oppressor accountable for what he did – unless the wronged person freely chooses to forgive the offender. In that case, God will not hold the offender accountable for the wrong he did on a human level (i.e., against the human he wronged), but unless he has obtained forgiveness from God for the wrong he did against God, he will still be held accountable for that.
Thus in our sins against others they are two dimensions – the human, by which we sin against our neighbor in the act, and the divine, by which we sin against God in the act. Thus theft is a sin against our neighbor from whom we stole and a sin against God, whose law we broke. We must obtain forgiveness from God for the divine aspect of our sin, but, as Jesus tells us in Matthew 5:25-26, we must obtain forgiveness for the human aspect of our sin from the human we sinned against. If we do not, God will hold us accountable.
Of course, since humans are finite beings, our sins against them can only merit finite punishment (compared to our sins against God, who is an infinite being, so our sins against him can merit infinite punishment). Because this punishment is finite, it must be temporary (for an eternal punishment is infinite since involves the reception of pain over an infinite period of time). But if this punishment we will receive when we are judged by God (according to Jesus’ parable) is temporary, then it’s purgatory. Thus Jesus says, “You will not get out until you have paid the last penny,” because there is a time when your finite punishment due to the finite, human dimension of your sins will be over.
In any event, more than enough has been said to show the inaccuracy of the charge that purgatory is an unbiblical doctrine. In reality, it is very firmly rooted in Scripture.