坐禪三昧經 2.55

2.55

若以厭患，起大悲心，愍念眾生，為此空骨，遠離涅槃，入三惡道，我當懃力，作諸功德，教化眾生，令解身相空，骨以皮覆，實聚不淨，為眾生故，徐當分別此諸法相。有少淨想，心生愛著；不淨想多，心生厭患；有出法相，故生實法。諸法實相中，無淨無不淨，亦無閉亦無出，觀諸法等，不可壞不可動，是名諸法實相（出過羅漢法也）。

If disgust gives rise to great compassion, pitying sentient beings who, on account of these empty bones, are far from nirvāṇa and enter the three bad destinies, [he vows:] 'I shall exert effort, cultivate virtues, and teach and transform sentient beings, making them understand that the body's marks are empty, bones covered with skin, truly an accumulation of impurity. For the sake of sentient beings, I shall gradually distinguish these marks of dharmas.' If there is a slight perception of purity, love and attachment arise in the mind; if there are many perceptions of impurity, disgust arises in the mind; because there are marks of dharmas that transcend, true dharmas arise. In the true mark of dharmas, there is neither pure nor impure, neither closure nor emergence; contemplating dharmas as equal, indestructible, and unshakeable—this is called the true mark of dharmas (transcending the arhat's dharma).