Plato, Meno 81b

διδόναι· λέγει δὲ καὶ Πίνδαρος καὶ ἄλλοι πολλοὶ τῶν ποιητῶν ὅσοι θεῖοί εἰσιν. ἃ δὲ λέγουσιν, ταυτί ἐστιν· ἀλλὰ σκόπει εἴ σοι δοκοῦσιν ἀληθῆ λέγειν. φασὶ γὰρ τὴν ψυχὴν τοῦ ἀνθρώπου εἶναι ἀθάνατον, καὶ τοτὲ μὲν τελευτᾶν—ὃ δὴ ἀποθνῄσκειν καλοῦσι—τοτὲ δὲ πάλιν γίγνεσθαι, ἀπόλλυσθαι δʼ οὐδέποτε· δεῖν δὴ διὰ ταῦτα ὡς ὁσιώτατα διαβιῶναι τὸν βίον· οἷσιν γὰρ ἂν— Φερσεφόνα ποινὰν παλαιοῦ πένθεος δέξεται, εἰς τὸν ὕπερθεν ἅλιον κείνων ἐνάτῳ ἔτεϊ ἀνδιδοῖ ψυχὰς πάλιν,

and many another poet of heavenly gifts. As to their words, they are these: mark now, if you judge them to be true. They say that the soul of man is immortal, and at one time comes to an end, which is called dying, and at another is born again, but never perishes. Consequently one ought to live all one’s life in the utmost holiness.For from whomsoever Persephone shall accept requital for ancient wrong, the souls of these she restores in the ninth year to the upper sun again; from them arise