Why we do not join the public festivals
Let us look also at what Celsus says next about God, and at how he urges us to make use of what are in truth things sacrificed to idols, or, if I may so call them, things sacrificed to demons, though he himself, since he does not know what is truly sacred or what kind of sacrifices are offered to God, would call them “sacred offerings.” What he says is this: “God at any rate is common to all, good, in need of nothing, and free from envy. What then prevents those who are most devoted to Him from taking part in the public festivals as well?”
I do not know what notion led him to think that it follows from God’s being good, in need of nothing, and free from envy, that those devoted to Him should take part in the public festivals. And I say that it would indeed follow from God’s being good, in need of nothing, and free from envy, that they should take part in the public festivals themselves, if it were proved that the public festivals have nothing amiss in them and were instituted from the contemplation of God as fitting for His service and for piety toward Him. If, however, the public festivals, which are festivals in name only, have no reasoned proof that they suit the service of the divine, but are shown to be fictions of men who instituted them haphazardly on account of certain human stories, or fictions that seem to contain natural lore about water or earth or the fruits the earth bears, then plainly those who wish to worship the divine with careful judgment would be acting reasonably in not taking part in the public festivals.
For “a festival,” as one of the Greek wise men well says, “is nothing other than doing what one ought” (Thucydides 1.70). And he truly keeps festival who does “what he ought,” praying always (1 Thessalonians 5:17), and continually offering the bloodless sacrifices in his prayers to the divine. That is why Paul’s words seem to me most lofty: “Do you observe days and months and seasons and years? I fear for you, that I may somehow have labored over you in vain” (Galatians 4:10–11).
Greek
Ἴδωμεν δὲ καὶ τὰ ἑξῆς Κέλσῳ λεγόμενα περὶ θεοῦ. καὶ ὡς προτρέπει ἡμᾶς ἐπὶ τὴν τῶν ὡς μὲν πρὸς ἀλήθειαν εἰδωλοθύτων χρῆσιν ἢ. ἵν᾿ οὕτως ὀνομάσω, δαιμονιοθύτων, ὡς δ᾿ αὐτὸς προσαγορεύσαι ἂν, ἅτε μὴ εἰδὼς, τί τὸ ἀληθῶς ἱερὸν, καὶ ποδαπαὶ αἱ παρὰ τούτῳ θυσίαι, ἱεροθύτων. ἃ δὲ λέγει, τοιαῦτά ἐστιν· ὅ γε μὴν θεὸς ἅπασι κοινὸς, ἀγαθός τε καὶ ἀπροσδεὴς καὶ ἔξω φθόνου· τί οὖν κωλύει τοὺς μάλιστα καθωσιωμένους αὐτῷ καὶ τῶν δημοτελῶν ἑορτῶν μεταλαμβάνειν; οὐκ οἶδα δὲ τί φαντασθεὶς οἴεται ἀκολουθεῖν τῷ τὸν θεὸν εἶναι ἀγαθὸν καὶ ἀπροσδεῆ καὶ ἔξω φθόνου τὸ τοὺς καθωσιωμένους αὐτῷ μεταλαμβάνειν τῶν δημοτελῶν ἑορτῶν. καί φημι ὅτι ἠκολούθει μὲν τῷ τὸν θεὸν εἶναι ἀγαθὸν καὶ ἀπροσδεῆ καὶ ἔξω φθόνου τὸ αὐτῶν τῶν δημοτελῶν μεταλαμβάνειν ἑορτῶν, εἰ ἀπεδείκνυτο ὅτι αἱ δημοτελεῖς ἑορταὶ οὐδὲν μὲν ἔχουσιν ἐσφαλμένον ἀπὸ δὲ τῆς περὶ θεοῦ θεωρίας ἐνομοθετήθησαν ὡς ἀκόλουθοι τῇ εἰς αὐτὸν θεραπείᾳ καὶ εὐσεβείᾳ. εἰ μέντοι αἱ δημοτελεῖς μέχρι ὀνόματος ἑορταὶ μηδένα λόγον ἔχουσιν ἀποδεικτικὸν, ὡς ἁρμόζουσαι τῇ εἰς τὸ θεῖον θεραπείᾳ, ἀλλ᾿ ἐλέγχοιντο οὖσαι ἀναπλάσματα τῶν ὅπως ποτὲ ἔτυχε διά τινας ἱστορίας ἀνθρωπικὰς ταῦτα νομοθετησάντων ἢ καὶ φυσιολογίας περὶ ὕδατος η γῆς ἢ τῶν ἀπ᾿ αὐτῆς καρπῶν δοκούντων περιέχειν, δῆλον ὅτι οἱ τὸ θεῖον ἐξητασμένως σέβειν θέλοντες εὔλογόν τι πράττοιεν, μὴ μεταλαμβάνοντες τῶν δημοτελῶν ἑορτῶν. „ἑορτὴ“ γὰρ, ὥς φησι τὶς καὶ τῶν Ἑλληνικῶν σοφῶν καλῶς λέγων. „οὐδὲν ἄλλο ἐστὶν ἢ τὸ τὰ δέοντα πράττειν“· καὶ ἑορτάζει γε κατὰ ἀλήθειαν ὁ „τὰ δέοντα“ πράττων, ἀεὶ εὐχόμενος, διὰ παντὸς θύων τὰς ἀναιμάκτους ἐν ταῖς πρὸς τὸ θεῖον εὐχαῖς θυσίας. διὸ καὶ μεγαλοφυέστατά μοι δοκεῖ παρὰ τῷ Παύλῳ εἰρῆσθαι τό· „ἡμέρας παρατηρεῖσθε καὶ μῆνας καὶ καιροὺς καὶ ἐνιαυτούς; φοβοῦμαι ὑμᾶς μή πως εἰκῇ κεκοπίακα εἰς ὑμᾶς.“