Kauṣītaki Upaniṣad 4.2.12

4.2.12

chāyāyāṃ dvitīyaḥ /

2. In the sun—the Great, in the moon—Food, in lightning—Truth, in thunder—Sound, in wind—Indra Vaikuṇṭha, in space—the Plenum, in fire—the Vanquisher, in water—Brilliance (tejas). —Thus with reference to the divinities (adhi-daivata). Now with reference to the self (adhy-ātma).— In the mirror—the Counterpart, in the shadow—the Double, in the echo—Life (asu), in sound—Death, in sleep—Yama [Lord of the dead], in the body—Prajāpati [Lord of Creation], in the right eye—Speech, in the left eye—Truth.