Laudator Temporis Acti

Aeschylus, Agamemnon 36-39 (tr. Herbert Weir Smyth):

For the rest I'm dumb; a great ox stands upon my tongue—yet the house itself, could it but speak, might tell a tale full plain; since, for my part, of mine own choice I have words for such as know, and to those who know not I've lost my memory.

τὰ δ' ἀλλὰ σιγῶ· βοῦς ἐπὶ γλώσσῃ μέγας
βέβηκεν· οἶκος δ' αὐτός, εἰ φθογγὴν λάβοι,
σαφέστατ' ἂν λέξειεν· ὡς ἑκὼν ἐγὼ
μαθοῦσιν αὐδῶ κοὐ μαθοῦσι λήθομαι.

John Ferguson, A Companion to Greek Tragedy (Austin: University of Texas Press, 1972; rpt. 1973), pp. 76-77:

He says, in picturesque language (36), "There's an ox on my tongue." He means, as the Greek commentator Zenobius tells us, that, as money talks, so also money (stamped with the image of the ox that represented wealth, as the Latin pecunia) can buy silence.

John Ferguson, Aeschylus, The Oresteia (Milton Keynes: Open University Press, 1979), p. 26:

A Greek commentator tells us that the ox signifies money. stamped with the image of the ox which represented wealth, i.e. money makes him hold his tongue. The English word 'pecuniary' comes from a Latin word of similar derivation. (I personally trust the Greek commentator against those modern scholars who reject his evidence and think that it is a homely proverb.)

In his sneer against "modern scholars" Ferguson probably had in mind Eduard Fraenkel, who in his commentary on Agamemnon (vol. II, p. 23) said:

The attempt at an explanation (βοῦς = money) found in Pollux 9.61, in the Paroemiographi (Diogenianus 3.48, i.223 Leutsch-Schneidcwin; cf. the passage quoted in their note), in Hesychius s.v. βοῦς ἐπὶ γλώσσηι (in the second place), and in Schol. BD on Homer Φ 79, is fatuous.

Likewise Liddell-Scott-Jones, s.v. , sense VIII:

wrongly expld. by Zen. 2.70, etc., of bribery with coins bearing type of ox.

Related post: An Ox on My Tongue.

Hat tip: Carl-Robert Boström.