Tiur-sa bréthir...

Tiur-sa bréthir ná scuriub-sa co brunni brátha 7 betha coro scuirea Amargin.

(I give * word * that not * I will desist * until * brink * of judgment * & * of life * until * may desist * Amargin)

I swear I'll never stop until Amargin stops.

So says Cú Ruí to Medb in the LL Táin, while he and Amargin are still engaged in assaulting one another with boulders. Cú Chulainn also uses this formula, "tiur-sa bréthir" (I give [my] word), elsewhere in the text. The other formulaic expression in this quotation, "co bruinni brátha ocus betha" (to the brink of [the last] judgment and of life), is likewise found elsewhere in the heroic literature. Fallamain, for example, uses it in the LU Táin when he promises not to return to Emain without Ailill's head. The expression "go broinne an bhrátha" is still used in Modern Irish.