妙法蓮華經玄義 4.71

4.71

阿那含天，用照鏡三昧。此聖無漏天，雖得淨色，但是報淨色。未究盡色空，如鏡未極明；未知色假，如鏡未有影；未知色中，如未達鏡圓。餘如上說。

For the Anāgāmin Heaven, the mirror-reflecting samādhi is used. Although these noble, outflow-free devas attain pure form, it is merely the pure form of retribution. They have not yet thoroughly penetrated the emptiness of form, like a mirror not yet fully bright; they do not yet know the provisionality of form, like a mirror not yet having reflections; and they do not yet know the Middle of form, like not yet understanding the roundness of the mirror. The rest is as explained above.