Here are some quotes from Plato, first on asceticism and then on purgatory.
ASCETICISM
Phaedo by Plato
Portrait of Socrates: Being the Apology, Crito, and Phaedo of Plato in an English translation by R. W. Livingstone; Clarendon Press, 1938.
“13. The virtue which is severed from wisdom and depends on these exchanges, is a painted show of virtue only, nor is there any freedom or health or truth in her; but thereality consists in a purification from all these things, and in temperance, and justice, and courage; and wisdom herself is a sort of purification. The founders of the Mysteries would appear to have had a real meaning, and were not talking nonsense when they intimated in a metaphor long ago that he who passes unsanctified and uninitiated into the world below will lie in the Slough, but that he who arrives there after initiation and purification will dwell with the gods. For ‘many’, as they say in the Mysteries, ‘are the Thyrsus-bearers, but few are the Mystics’–meaning by the latter, as I interpret the words, ‘the true philosophers’.”
“32. The role of philosophy in life. Starting from a different point from religion, it impresses on men the same lessons as religion–the misleading and transitory nature of the world of the senses, the superior reality of the unseen world. No one who has not studied philosophy and who is not entirely pure when he leaves this world is allowed to enter the company of the gods, but the lover of knowledge only. And this is the reason, Simmias and Cebes, why the true votaries of philosophy abstain from all the desires of the body, and hold out against them and refuse to give themselves up to them-not because they fear poverty or the ruin of their families, like the lovers of money, and the world in general; nor like the lovers of power and honour, because they dread the dishonour or disgrace of wrong conduct.
No, Socrates, that would not become them, said Cebes.
No indeed, he replied; and therefore they who have any care of their own souls, and do not merely live moulding and fashioning the body, turn their backs on all this; they will not walk in the ways of the blind: and when philosophy offers them purification and release from evil, they feel that they ought not to resist her influence, and whither she leads they turn and follow.”
PURGATORY
“62. SUCH is the nature of the other world; and when the dead arrive at the place to which the genius of each severally guides them, first of all, they have sentence passed upon them, as they have lived good and holy lives or not. Those who appear to have lived neither well nor ill go to the river Acheron, and embarking in any vessels which they may find, are carried in them to the lake; there they dwell and are purified of their evil deeds, and having suffered punishment for the wrongs which they have done to others, they are absolved, and receive the rewards of their good deeds, each of them according to his deserts. But those whose crimes are so great that they seem to be incurable–who have committed many and terrible deeds of sacrilege, murders foul and violent, or the like–such are thrown into Tartarus by the fate which is their due, and they never come out. Those, again, who have committed crimes, which, although great, are not irremediable–who in a moment of anger, for example, have done some violence to a father or a mother, and have repented for the remainder of their lives, or who have taken the life of another under the like extenuating circumstances-these are plunged into Tartarus, the pains of which they are compelled to undergo for a year, but at the end of the year the wave casts them forth-mere homicides by way of Cocytus, parricides and matricides by Pyriphlegethon–and they are borne to the Acherusian lake, and there they lift up their voices and call upon the victims whom they have slain or wronged, to have pity on them, and to be kind to them, and let them come out into the lake. If they prevail, then they come forth and cease from their troubles; but if not, they are carried back again into Tartarus and from thence into the rivers unceasingly, until they obtain mercy from those whom they have wronged; for that is the sentence passed upon them by their judges. Those, too, who have been pre-eminent for holiness of life are released from this earthly prison, and go to their pure home which is above, and dwell in the purer earth; and of these, such as have duly purified themselves with philosophy, live henceforth altogether without the body, in mansions fairer still, which may not be described, and of which now I have no time to tell. So, Simmias, seeing all these things, what ought not we to do that we may obtain virtue and wisdom in this life? Fair is the prize, and the hope great!”