釋禪波羅蜜次第法門 3.29

3.29

不淨觀門約此五處為緣，令心不散，以辨修繫緣止，意在於此。譬如猨猴得樹，騰躍跳躑，若鎖之於柱，久久自調。心亦如是，若心停住，未入定前復有一止，名凝心止。若得入定，身心泯然，任運自寂，即是入定止。

The contemplation gates of impurity take these five places as conditions to make the mind non-distracted, in order to distinguish the cultivation of 'stopping by tying to conditions'—such is the intent here. For example, when a monkey gets to a tree, it leaps and bounds about, but if tied to a pillar, over a long time it naturally becomes tamed. The mind is also like this. If the mind comes to rest, before entering absorption there is another stopping, called 'stopping through concentrating the mind'. If one manages to enter absorption, body and mind are obliterated, naturally tranquil of their own accord, which is 'stopping upon entering absorption'.