When the lips perish, the teeth become frigid

The Lord of the Tanzhe Plain once more sought to assail Kua by way of Ou. Kui Ku Ren-xi reproved the duke of Ou, saying, "Kua is exterior to Ou. If Kua should perish, Ou is bound to follow. The route should not be yielded for the Tanzhe Lord. Brigands are not to be dallied with. Once was more than enough, how can you do it a second time? The two expressions, 'The coach and its bracing rods rely on one another' and 'When the lips perish, the teeth become frigid,' both pertain to the relationship between Kua and Ou.