Kaushitaki Upanishad

The Kaushitaki Upanishad (Sanskrit: कौषीतकि उपनिषद्, Kauṣītaki Upaniṣad) is an ancient Sanskrit text contained inside the Rigveda. It is associated with the Kaushitaki shakha, but a Sāmānya Upanishad, meaning that it is "common" to all schools of Vedanta. It was included in Robert Hume's list of 13 Principal Upanishads, and lists as number 25 in the Muktika canon of 108 Upanishads.

Quotes

 * They say ‘The eye came; it was a serpent; thus did poison come to the priests; he used these (verses) connected with (Soma) the purifying, and repelling poison, in praise’.
 * Kausitaki Brahmana 29, 1. Quoted from Kazanas, N. (2009). Indo-Aryan origins and other Vedic issues. Chapter 8