προσέχειν τὸν νοῦν
From LSJ
ἀρχὴν μὲν μὴ φῦναι ἐπιχθονίοισιν ἄριστον· φύντα δ' ὅμως ὤκιστα πύλας Ἀίδαο περῆσαι → First, it is best for mortals to not be born. If born, to pass through Hades' gates as soon as possible.
Greek > English (Woodhouse)
heed, mark, note, notice, apply one's mind to, attend to, bestow attention, pay attention to, pay attention