from PHAEDO

Then tell me, Socrates, why is suicide held not to be right? as I have certainly heard Philolaus affirm when he was staying with us at Thebes: and there are others who say the same, although none of them has ever made me understand him.

But do your best, replied Socrates, and the day may come when you will understand. I suppose that you wonder why, as most things which are evil may be accidentally good, this is to be the only exception (for may not death, too, be better than life in some cases?), and why, when a man is better dead, he is not permitted to be his own benefactor, but must wait for the hand of another.

ΦΑΙΔΩΝΟΣ  

Κατὰ τί δὴ οὖν ποτε οὔ φασι θεμιτὸν εἶναι αὐτὸν ἑαυτὸν ἀποκτεινύναι͵ ὦ Σώκρατες; ἤδη γὰρ ἔγωγε͵ ὅπερ νυνδὴ σὺ ἤρου͵ καὶ Φιλολάου ἤκουσα͵ ὅτε παρ΄ ἡμῖν διῃτᾶτο͵ ἤδη δὲ καὶ ἄλλων τινῶν͵ ὡς οὐ δέοι τοῦτο ποιεῖν· σαφὲς δὲ περὶ αὐτῶν οὐδενὸς πώποτε οὐδὲν ἀκήκοα.

Ἀλλὰ προθυμεῖσθαι χρή͵ ἔφη· τάχα γὰρ ἂν καὶ ἀκούσαις. ἴσως μέντοι θαυμαστόν σοι φανεῖται εἰ τοῦτο μόνον τῶν ἄλλων ἁπάντων ἁπλοῦν ἐστιν͵ καὶ οὐδέποτε τυγχάνει τῷ ἀνθρώπῳ͵ ὥσπερ καὶ τἆλλα͵ ἔστιν ὅτε καὶ οἷς βέλτιον ὂν τεθνάναι ἢ ζῆν͵ οἷς δὲ βέλτιον τεθνάναι͵ θαυμαστὸν ἴσως σοι φαίνεται εἰ τούτοις τοῖς ἀνθρώποις μὴ ὅσιον αὐτοὺς ἑαυτοὺς εὖ ποιεῖν͵ ἀλλὰ ἄλλον δεῖ περιμένειν εὐεργέτην.