ἐκπονεῖν
From LSJ
ὃν οὐ τύπτει λόγος οὐδὲ ῥάβδος → if words don't get through, neither a beating will | if the carrot doesn't work, the stick will not work either | whom words do not strike, neither does the rod
Greek > English (Woodhouse Verbs Reversed)
(see also ἐκπονέω): earn, acquire by labour, bring to perfection, bring to success by effort, carry through by effort, digest food, labor out, labour out, make by work, make perfect, win by labor, win by labour, work out, work up
Lexicon Thucydideum
elaborare, excolere, to work diligently at, cultivate, 3.38.2,
PASS. 6.31.3.