Plutarch Consolatio Ad Uxorem 10

[10] As for what you hear others say, who persuade the vulgar that the soul, when once freed from the body, suffers no inconvenience or evil nor is sensible at all, I know that you are better grounded in the doctrines delivered down to us from our ancestors, as also in the sacred mysteries of Bacchus, than to believe such stories; for the religious symbols are well known to us who are of the fraternity. Therefore be assured, that the soul, being incapable of death, is affected in the same manner as birds that are kept in a cage. For if she has been a long time educated and cherished in the body, and by long custom has been made familiar with most things of this life, she will (though separable) return again, and at length enter the body; nor ceaseth it by new births now and then to be entangled in the chances and events of this life. For do not think that old age is therefore evil spoken of and blamed, because it is accompanied with wrinkles, gray hairs, and weakness of body. But this is the most troublesome thing in old age, that it maketh the soul weak in its remembrance of divine things, and too earnest for things relating to the body; thus it bendeth and boweth, retaining that form which it took of the body. But that which is taken away in youth, being more soft and tractable, soon returns to its native vigor and beauty. Just as fire that is quenched, if it be forthwith kindled again, sparkles and burns out immediately.... So most speedily before too great a love of bodily and earthly things be engendered in the soul, and it become soft and tender by being used to the body, and (as it were) by charms and potions incorporated with it.