πέτρην κοιλαίνει ρανὶς ὕδατος ἐνδελεχείῃ → constant dropping wears away a stone, constant dripping will wear away the hardest stone, little strokes fell big oaks, constant dripping wears the stone, constant dropping wears the stone, constant dripping will wear away a stone
endeavour: P. and V. πεῖρα, ἡ; see attempt.
wearing: P. and V. βαρύς, Ar. and P. χαλεπός; see irksome.