Śaṅkaraon Brahma Sūtra 4.4.20

Scripture and both declare that the highest light does not abide within effected things, ‘ The sun does not shine there, nor the moon and the stars, nor these lightnings, and much less this fire* (Mu. Up. II, 2, 10). ‘The sun does not illume it, nor the moon, nor fire* (Bha. Gita XV, 6). —The Sutra is meant to show that the non-abiding of the highest light within effected things is a well-known circumstance.