俱舍論頌疏論本 26.59

26.59

釋曰：性俗三九善者，性謂三性門，俗智通三性，餘九智唯善也。

The commentary explains: "In nature, the conventional is of three; nine are wholesome": 'nature' refers to the category of the three moral natures; conventional knowledge is common to all three natures, whereas the remaining nine knowledges are solely wholesome.