εἰσιτέον
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
English (LSJ)
one must go in, Iamb.VP23.105, al.
Spanish (DGE)
hay que ir εἰ. εἴσω δ' ἐστίν Men.Cith.63, cf. Iambl.VP 105.