παραδειγματιστέον
From LSJ
Ἃ δέ σοι συνεχῶς παρήγγελλον, ταῦτα καὶ πρᾶττε καὶ μελέτα, στοιχεῖα τοῦ καλῶς ζῆν ταῦτ' εἶναι διαλαμβάνων (Epicurus, Letter to Menoeceus 123.2) → Carry on and practice the things I incessantly used to urge you to do, realizing that they are the essentials of a good life.
English (LSJ)
A one must punish for example's sake, Id.35.2.10.
Greek (Liddell-Scott)
παραδειγματιστέον: ῥηματ. ἐπίθετ. τοῦ παραδειγματίζω, δεῖ παραδειγματίζειν, Πολύβ. 35. 2, 10.