大般涅槃經義記 10.147

10.147

上來觀色，下次觀心。「如內外色心法亦爾」舉色類心，「何以」下釋。釋中，初言「行六處者緣境不同」顯心無常。「或生喜」等，改變不定顯心無常。

The preceding was the contemplation of form; next is the contemplation of mind. "As with internal and external form, mental phenomena are also thus" cites form to analogize mind; from "Why?" downward is the explanation. In the explanation, first the statement "those who practice the six sense-spheres take different objects of cognition" reveals the impermanence of mind. "Sometimes giving rise to joy," and so forth, reveals the impermanence of mind through unstable changing.