妙法蓮華經文句 1.62

1.62

觀解者，觀住於境，或住無常境，即空、即假、即中等境，以無住法住於境中故名為住。

In terms of contemplation: Contemplation abides in the cognitive object—either abiding in the object of impermanence, or in objects that are identically empty, identically provisional, identically the middle, and so forth; because it abides in objects by means of the dharma of non-abiding, it is called 'abiding'.