Passage 4.25.4
μετεβουλεύετό τε δή σφισι καὶ αὐτίκα ἐπὶ Μεσσηνίους τρέπονται τοὺς ἐν Οἰνιάδαις. καὶ οἱ μὲν ὡς πολιορκήσοντες παρεσκευάζοντο· οὐ γάρ ποτε ὑπελάμβανον ἄνδρας οὕτως ὀλίγους ἐς τοσοῦτον ἀπονοίας ἥξειν ὡς μαχέσασθαι πρὸς τὴν Ἀκαρνάνων ἁπάντων στρατιάν. οἱ δὲ Μεσσήνιοι προητοιμασμένοι μὲν καὶ σῖτον καὶ τὰ ἄλλα ἦσαν ὁπόσα εἰκὸς ἦν, πολιορκίας πειράσεσθαι μακροτέρας ἐλπίζοντες·
So after reconsideration, the Acarnanians immediately turned themselves against the Messenians in Oeniadae. They prepared as if about to besiege them, for they never supposed that men so few in number would reach such madness as to fight openly against the whole force of the Acarnanians. The Messenians, however, had previously stocked up food and all other things which might reasonably be needed, expecting they would face a prolonged siege.