俱舍論記 17.31

17.31

「彼依究竟至名能斷善根」者，通。本論云逆順說斷，如前可知。斷前八品雖亦名斷，斷猶未盡，至斷第九方究竟盡。彼依究竟，密說此言。上品不善根能斷善根，非前八品不能斷善。

Regarding "That relies upon the ultimate ... is called able to sever the wholesome roots": Resolution. The root treatise speaks of severing in reverse and direct order, as understood previously. Although severing the first eight grades is also called severing, the severing is not yet exhausted; only upon severing the ninth is it ultimately exhausted. Relying on the ultimate, it made this statement implicitly: the highest grade of unwholesome roots can sever the wholesome roots, but this does not mean the first eight grades cannot sever the wholesome.