2 Maccabees 12:43-46
And making a gathering, he sent twelve thousand drachms of silver to Jerusalem for sacrifice to be offered for the sins of the dead, thinking well and religiously concerning the resurrection,
(For if he had not hoped that they that were slain should rise again, it would have seemed superfluous and vain to pray for the dead,)
And because he considered that they who had fallen asleep with godliness, had great grace laid up for them.
It is therefore a holy and wholesome thought to pray for the dead, that they may be loosed from sins.
Maccabees is not part of the Bible