Passage 4.20.7
καί ποτε ἔτυχε σὺν ἄλλοις ἐς ἐκεῖνον περιήκουσα ἐν τῇ νυκτὶ ἡ φυλακή, ἔτυχε δὲ καὶ ὕειν πολλῷ τὸν θεόν, καὶ ἐκλείπουσιν οἱ Μεσσήνιοι τὴν φρουράν· τὸ γὰρ ὕδωρ ἐβιάζετο σφᾶς ἀθρόον ἐκ τοῦ οὐρανοῦ καταχεόμενον, οὔτε ἐπάλξεων ἐνῳκοδομημένων οὔτε πύργων ὑπὸ σπουδῆς τοῦ τειχισμοῦ, καὶ ἅμα οὐδὲ κινήσεσθαι τοὺς Λακεδαιμονίους ἤλπιζον ἐν ἀσελήνῳ νυκτὶ καὶ οὕτω χειμερίῳ.
And once it happened that a guard post at that place had fallen to him and others during the night. It happened also that the god sent down heavy rain, and the Messenians abandoned their guard-post; for the water, pouring from heaven abundantly, overwhelmed them. Moreover, neither parapets nor towers had been built due to the haste of the fortification, and they did not expect that the Lacedaemonians would move against them on a gloomy and such stormy night.