χάριν θέσθαι
From LSJ
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
