Jaiminīya Upaniṣad Brāhmaṇa 2.7.10

2.7.10

atha hovācāyāsyam āṅgirasaṃ yan me tvam udgāyeḥ kiṃ tatas syād iti /

Then he said to Ayāsya Āṅgirasa: “If you were to chant for me, what would result from it?”