Consider these words from the Second Book of Maccabees:
Judas Maccabeus then took up a collection among all his soldiers, amounting to 2,000 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 (2 Macc. 12:43).
These words from one of the latest Books of the Old Testament are the earliest statement of the doctrine that prayers and sacrifices for the dead are efficacious. The statement here proves that Judas Maccabeus believed in the Resurrection of the just, a startling new revelation from God for pre-Christian times. Clearly he believed that expiation could be made for the sins of otherwise good men-soldiers who had given their lives for God’s cause. Thus, they could share in the final Resurrection. Under the guidance of the Holy Spirit, his belief would gradually develop into the Catholic doctrine of purgatory. As the diocese prays for its deceased priests and deacons, all Catholics are reminded of the benefit of praying for the dead that, indeed, “they might be loosed of their sins” and enter quickly into the fullness of resurrected life.