俱舍論頌疏論本 28.45

28.45

釋曰：第四靜慮無八災患動，是故世尊說名不動。災患有八，所謂尋、伺、憂、苦、喜、樂、出息、入息。有餘師說，第四靜慮如密室燈，照而無動，故名不動。

Explanation: The fourth dhyāna is free from agitation by the eight afflictions; therefore, the World-Honoured One called it 'unshakeable.' The afflictions are eight: namely, investigation, examination, sorrow, pain, joy, bliss, exhalation, and inhalation. Other masters say that the fourth dhyāna is like a lamp in a closed room, illuminating without shaking; therefore, it is called unshakeable.