Shameless Popery says:
The Second Book of Maccabees is completely straightforward about praying for the departed, and praying to the Saints. In 2 Macc. 12:43-46, some of Judas Maccabeus’ soldiers fall in combat. Although they’re fighting for Israel, the Israelites discover superstitious amulets on the fallen soldiers, and realize this is why they were allowed to fall. Maccabeus responds to this by praying for the dead, and offering a sin offering on their behalf:
He also took up a collection, man by man, to the amount of two thousand drachmas of silver, and sent it to Jerusalem to provide for a sin offering. In doing this he acted very well and honorably, taking account of the resurrection. For if he were not expecting that those who had fallen would rise again, it would have been superfluous and foolish to pray for the dead. But if he was looking to the splendid reward that is laid up for those who fall asleep in godliness, it was a holy and pious thought.Therefore he made atonement for the dead, that they might be delivered from their sin. You can’t get much clearer then that. The Bible tells us that he prayed for the dead, praises him for it, and then tells us that he thereby made atonement for them that they might be delivered from their sin. All of this is linked to the resurrection of the dead, which puts the author of 2 Maccabees ahead of the Sadducees when it comes to orthodoxy (cf. Luke 20:27).
Detractor in the comment box:
Concerning 2 Maccabees. It has been a few years since I read this book, but I think even in what you quoted you have a few problems. First, idolatry is a mortal sin and they died in their mortal sin. Prayers cannot avail those who have not done penance for such a sin. So, if you interpret 2 Maccabees as Scriptural proof of prayers for the dead, you just eviscerated your own dogma.
Shameless Popery says:
Underlying your confidence that the fallen are in Hell is the idea that they were idolaters. But it doesn’t actually say that in the Bible. Rather it says that the fallen were wearing the “sacred tokens of the idols of Jam′nia, which the law forbids the Jews to wear” (2 Macc. 12:40). So maybe they were idolaters, or maybe they were just superstitious. But err on the side of praying for them, obviously!