περιίσχειν

From LSJ

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

Source

Lexicon Thucydideum

superare, to surpass, overcome, 5.71.1.