εὐσεβεῖν

From LSJ

βορβόρῳ δ' ὕδωρ λαμπρὸν μιαίνων οὔποθ' εὑρήσεις ποτόν → once limpid waters are stained with mud, you'll never find a drink

Source

Greek > English (Woodhouse Verbs Reversed)

(see also εὐσεβέω): keep a clear conscience, practise holiness