Biblical source, please, book(s), chapter(s), verses.
Signed: A seriously inquisitive seeker, in re purgatory.
Scripture from the Greek Septuagint, the Old Testament of Christ, the Evangelists and Paul, and of the councils of Hippo and Carthage, affirm purgatory.
2 Mc 12:42-46
Turning to supplication, they prayed that the sinful deed might be fully blotted out. The noble Judas warned the soldiers to keep themselves free from sin, for they had seen with their own eyes what had happened because of the sin of those who had fallen. He then took up a collection among all his soldiers, amounting to two thousand silver drachmas, which he sent to Jerusalem to provide for an expiatory sacrifice. In doing this he acted in a very excellent and noble way, inasmuch as he had the resurrection of the dead in view; for if he were not expecting the fallen to rise again, it would have been useless and foolish to pray for them in death. But if he did this with a view to the splendid reward that awaits those who had gone to rest in godliness, it was a holy and pious thought. Thus he made atonement for the dead that they might be freed from this sin.
Even just Maccabees is sufficient to knock down the, "that's not in Scripture" stuff.
Search for "Scott Hahn and Purgatory" and you can find a good lecture he gave on the topic that goes over a good many other verses as well. Turtullian defended the doctrine of Purgatory in something like 160AD which shuts down the arguments about it having been made up at some late date.