兩國相爭，不斬來使 [两国－争－－斩来－]

Jyutping loeng5 gwok3 soeng1 zang1, bat1 zaam2 loi4 si3
Pinyin liǎng guó xiāng zhēng , bù zhǎn lái shǐ

Definitions (CC-CEDICT)
  1. when two kingdoms are at war, they don't execute envoys (idiom)