Laudator Temporis Acti

Agathias, Histories 2.23.8 (tr. Joseph D. Frendo):

It is quite obvious, of course, that each of the various nations of mankind considers that any custom whatsoever which is both universally accepted in their society and deeply rooted in their past cannot fail to be perfect and sacrosanct, whereas whatever runs counter to it is deemed deplorable, contemptible and unworthy of serious consideration. Nevertheless people have always managed to find and enlist the support of reasoned arguments from all quarters when their own conventions are involved. Such arguments may indeed be true, but they may also very well be specious fabrications.

καἰ εὔδηλον μὲν ὅτι δὴ τῶν ἀνθρωπείων ἐθνῶν ὡς ἕκαστοι, εἰ γε ὁτῳ δη οῦν νόμῳ ἐκ πλείστου νενικηκότι ἐμβιοτεύσαιεν, τοῦτον δὴ ἄριστον ἡγοῦνται καὶ θεσπέσιον, καὶ εἴ πού τι παρ' ἐκεῖνον πράττοιτο, φευκτόν τε αὐτοῖς εἶναι δοκεῖ καὶ καταγέλαστον καὶ ὁποῖον ἤδη καὶ ἀπιστεῖσθαι. ἐξεύρηνται δὲ ὅμως αἰτίαι τοῖς ἀνθρώποις καὶ λόγοι τῶν οἰκείων πέρι νόμων ἄλλοθι ἄλλοι, τυχὸν μὲν ἀληθεῖς, τυχὸν δὲ καὶ ἐς τὸ πιθανώτερον ἐσκευασμένοι.