Kaṭhopaniṣad 2.19-20—Calming the Senses

“If the killer thinks (of It) in terms of killing, and if the killed thinks (of It) as killed, both of them do not know. It does not kill, nor is it killed. The Self that is subtler than the subtle and greater than the great is lodged in the heart of (every) creature. A desireless man sees that glory of the Self through the serenity of the organs, and (thereby he becomes) free from sorrow.“