strongly

From LSJ

πολλάκις δοκεῖ τὸ φυλάξαι τἀγαθὰ τοῦ κτήσασθαι χαλεπώτερον εἶναι → it often proves harder to keep than to win prosperity | it is often harder for men to keep the good they have, than it was to obtain it

Source