δαμαστέον
From LSJ
μή, φίλα ψυχά, βίον ἀθάνατον σπεῦδε, τὰν δ' ἔμπρακτον ἄντλει μαχανάν → Oh! my soul do not aspire to eternal life, but exhaust the limits of the possible. | Do not yearn, O my soul, for immortal life! Use to the utmost the skill that is yours. | Do not, my soul, strive for the life of the immortals, but exhaust the practical means at your disposal.
English (LSJ)
A one must break in, τριετῆ πῶλον Gp.16.1.11. II Adj. -τέος, α, ον, Hsch. s.v. δματέα.