Kaṭha Upaniṣad 92

92

jānāmy ahaṃ śevadhir ity anityaṃ na hy adhruvaiḥ prāpyate hi dhruvaṃ tat /
tato mayā nāciketaś cito 'gnir anityair dravyaiḥ prāptavān asmi nityam ///1,2.10 //

10. I know that the treasure is uncertain; for, that which is constant is never reached by things which change. Therefore, has Nachiketa fire been propitiated by me with the perishable things, and I have attained the eternal.