Go look up every time Jesus Christ used the word "Gehenna".
That IS Purgatory, and Hell, both. Whether it ends up being one or the other depends on whether the soul gets out or not.
And yes, I have my books now, but I am at work, so no, I cannot cite you specific chapter and verse until this evening.
Purgatory is in the Bible: Gehenna. Jesus says it a lot.
Also consult 2 Maccabbees for an instance of prayers of atonement for the souls of the dead.
But again, to give you specific chapter and verse, as on the other thread, I must have the book in front of me (which I do) and the time (which I don't, right now, but will this week). So, keep a running list as I am trying to do, and I will give you your Scripture, line by line.
For Purgatory/Hell, it's simple: find Jesus referring to Gehenna, and go look up the ancient Jewish understanding of Gehenna. Jesus didn't correct that, as he did Scripture which contained erroneous tradition (e.g.: marriage and divorce, with the divorce laws referenced in the Torah not ever having been the law of God).
Those folks have hacked the books of Maccabees out of their (abridged) "Bibles". That's far more offensive than when they ignore the passages which they haven't hacked out (but which refute their false doctrines).
And so we see the crux of the reason for the RCC's addition of the Apocrypha to their bible. If it ain't in Scripture, add more text.
As far as the concept of Gehenna and Hell being the same place. Prior to the revelation of God's plan of salvation through the sacrifice of His Son, it is not likely that anyone would have a separate concept of the two. We know from the parable of Lazarus and the rich man that, indeed, there is a temporary place for souls - and an unbridgeable chasm between the paradisical "bossom of Abraham" and torment.
Your Purgatory would allow this unbridgeable chasm become bridgeable to paradise. However we know that the only bridge is from this temporary torment, Gehenna, to Hell.
The Bible clearly teaches that man has one shot to determine where he will spend his eternal existence. Hebrews 9:7: And as it is appointed for men to die once, but after this the judgment. There is no second chance, and neither we nor our relatives can buy or otherwise earn our way out of God's justice.
"Also consult 2 Maccabbees for an instance of prayers of atonement for the souls of the dead."
Idol worshipers were to be stoned in Israel. There was to be no mercy shown to them so how does your reference to Judas praying for idol worshiping soldiers who were killed for their sin, prove you point? In fact, aren't those who die worshiping idols as far as the Roman Church is concerned, guilty of a mortal sin and beyond the mercy of God?