ἄνω ποταμῶν ἱερῶν χωροῦσι παγαί

From LSJ

πάντες γὰρ οἱ λαβόντες μάχαιραν ἐν μαχαίρῃ ἀπολοῦνται → all they that take the sword shall perish with the sword

Source