Passage 8.10.9
πολέμῳ δὲ καὶ ἀνθρώπων φόνοις παρεῖναι θεοὺς ἐποίησαν μὲν ὅσοις τὰ ἡρώων ἐμέλησεν ἐν Ἰλίῳ παθήματα, ᾄδεται δὲ ὑπὸ Ἀθηναίων ὡς θεοί σφισιν ἐν Μαραθῶνι καὶ ἐν Σαλαμῖνι τοῦ ἔργου μετάσχοιεν· ἐκδηλότατα δὲ ὁ Γαλατῶν στρατὸς ἀπώλετο ἐν Δελφοῖς ὑπὸ τοῦ θεοῦ καὶ ἐναργῶς ὑπὸ δαιμόνων. οὕτω καὶ Μαντινεῦσιν ἕπεται οὐκ ἄνευ τοῦ Ποσειδῶνος τὸ κράτος γενέσθαι σφίσι.
As for the presence of gods in warfare and the slaughter of men, those concerned with the sufferings of heroes at Ilium have affirmed this; and the Athenians sing of how the gods took part in their deeds at Marathon and Salamis. But most clearly of all, the host of the Gauls was destroyed at Delphi by divine agency, manifestly through supernatural powers. Thus the Mantineans also attribute their victory explicitly to the assistance of Poseidon.