Plato, Laws 931a

τῶν θεῶν ὁρῶντες σαφῶς τιμῶμεν, τῶν δʼ εἰκόνας ἀγάλματα ἱδρυσάμενοι, οὓς ἡμῖν ἀγάλλουσι καίπερ ἀψύχους ὄντας, ἐκείνους ἡγούμεθα τοὺς ἐμψύχους θεοὺς πολλὴν διὰ ταῦτʼ εὔνοιαν καὶ χάριν ἔχειν. πατὴρ οὖν ὅτῳ καὶ μήτηρ ἢ τούτων πατέρες ἢ μητέρες ἐν οἰκίᾳ κεῖνται κειμήλιοι ἀπειρηκότες γήρᾳ, μηδεὶς διανοηθήτω ποτὲ ἄγαλμα αὑτῷ, τοιοῦτον ἐφέστιον ἵδρυμα ἐν οἰκίᾳ ἔχων, μᾶλλον κύριον ἔσεσθαι, ἐὰν δὴ κατὰ τρόπον γε ὀρθῶς αὐτὸ θεραπεύῃ ὁ κεκτημένος.

of all men concerning the gods are two-fold: some of the gods whom we honor we see clearly, but of others we set up statues as images, and we believe that when we worship these, lifeless though they be, the living gods beyond feel great good-will towards us and gratitude. So if any man has a father or a mother, or one of their fathers or mothers, in his house laid up bed-ridden with age, let him never suppose that, while he has such a figure as this upon his hearth, any statue could be more potent, if so be that its owner tends it duly and rightly.