Plato, Laws 941a

ἐὰν ὡς πρεσβευτής τις ἢ κῆρυξ καταψευδόμενος τῆς πόλεως παραπρεσβεύηται πρός τινα πόλιν, ἢ πεμπόμενος μὴ τὰς οὔσας πρεσβείας ἐφʼ αἷς πέμπεται ἀπαγγέλλῃ, ἢ πάλιν αὖ παρὰ τῶν πολεμίων ἢ καὶ φίλων μὴ τὰ παρʼ ἐκείνων ὀρθῶς ἀποπρεσβεύσας γένηται φανερὸς ἢ κηρυκεύσας, γραφαὶ κατὰ τούτων ἔστων ὡς Ἑρμοῦ καὶ Διὸς ἀγγελίας καὶ ἐπιτάξεις παρὰ νόμον ἀσεβησάντων, τίμημα δὲ ὅτι χρὴ

If anyone, while acting as ambassador or herald, conveys false messages from his State to another State, or fails to deliver the actual message he was sent to deliver, or is proved to have brought back, as ambassador or herald, either from a friendly or hostile nation, their reply in a false form,—against all such there shall be laid an indictment for breaking the law by sinning against the sacred messages and injunctions of Hermes and Zeus, and an assessment shall be made of the penalty they shall suffer or pay,