Garudapurana 1.36.17

1.36.17

taṃ hanti sūryaḥ sandhyāyāṃ nopāstiṃ kurute tu yaḥ /
turīyasya padasyāpi ṛṣirnirmala eva ca //

The sun destroys him who does not perform worship at twilight. / The seer of this fourth foot also is the Stainless One;