Pausanias 8.2.4-5 (tr. W.H.S. Jones):
For the men of those days, because of their righteousness and piety, were guests of the gods, eating at the same board; the good were openly honoured by the gods, and sinners were openly visited with their wrath. Nay, in those days men were changed to gods, who down to the present day have honours paid to them—Aristaeüs, Britomartis of Crete, Heracles the son of Alcmena, Amphiaraüs the son of Oicles, and besides these Polydeuces and Castor. So one might believe that Lycaon was turned into a beast, and Niobe, the daughter of Tantalus, into a stone.
But at the present time, when sin has grown to such a height and has been spreading over every land and every city, no longer do men turn into gods, except in the flattering words addressed to despots, and the wrath of the gods is reserved until the sinners have departed to the next world.
οἱ γὰρ δὴ τότε ἄνθρωποι ξένοι καὶ ὁμοτράπεζοι θεοῖς ἦσαν ὑπὸ δικαιοσύνης καὶ εὐσεβείας, καί σφισιν ἐναργῶς ἀπήντα παρὰ τῶν θεῶν τιμή τε οὖσιν ἀγαθοῖς καὶ ἀδικήσασιν ὡσαύτως ἡ ὀργή, ἐπεί τοι καὶ θεοῖ τότε ἐγίνοντο ἐξ ἀνθρώπων, οἳ γέρα καὶ ἐς τόδε ἔτι ἔχουσιν ὡς Ἀρισταῖος καὶ Βριτόμαρτις ἡ Κρητικὴ καὶ Ἡρακλῆς ὁ Ἀλκμήνης καὶ Ἀμφιάραος ὁ Ὀικλέους, ἐπὶ δὲ αὐτοῖς Πολυδεύκης τε καὶ Κάστωρ. οὕτω πείθοιτο ἄν τις καὶ Λυκάονα θηρίον καὶ τὴν Ταντάλου Νιόβην γενέσθαι λίθον.
ἐπ᾿ ἐμοῦ δὲ—κακία γὰρ δὴ ἐπὶ πλεῖστον ηὔξετο καὶ γῆν τε ἐπενέμετο πᾶσαν καὶ πόλεις πάσας—οὔτε θεὸς ἐγίνετο οὐδεὶς ἔτι ἐξ ἀνθρώπου, πλὴν ὅσον λόγῳ καὶ κολακείᾳ πρὸς τὸ ὑπερέχον, καὶ ἀδίκοις τὸ μήνιμα τὸ ἐκ τῶν θεῶν ὀψέ τε καὶ ἀπελθοῦσιν ἐνθένδε ἀπόκειται.