Republic

For this reason Plato said in the third book of the Republic—he whom they most invoke as their witness in disparaging generation—that one must care for the body for the sake of the soul's harmony, through which it is possible to live and to live rightly, proclaiming the message of the truth;

Yet this is the uttermost limit of injustice, if we are to believe Plato at all:

Nor do you relax at all in your zeal for letters, but, as Plato says, in the storm and tempest of affairs, standing apart as it were beneath some strong wall, you fill your soul with no disturbance;

The former, as the Greek word shows, signifies trade or exchange between widely separated nations, and it ranks first in the order of Nature, as is shown in Plato’s Republic.

Do not hope for Plato's Republic, but be content if the smallest thing goes forward, and reflect how small a matter even the outcome of that is.

For to this end Plato too, although he dispatches what souls he will to heaven straightway, yet in the Republic opposes the corpse of a certain unburied man preserved a long time without any decay — on account, namely, of the indivisibility of the soul.