Jaiminīya Upaniṣad Brāhmaṇa 3.28.5

3.28.5

tad u hovāca śāṭyāyanir bahuvyāhito vā ayam bahuśo lokaḥ
etasya vai kāmāya nu bruvate [vā] śrāmyanti vā ka etat prāsya punar iheyād atraiva syād iti /
pañcame 'nuvāke navamaḥ khaṇḍaḥ
pañcamo 'nuvākas samāptaḥ //

And on this Śāṭyāyani used to say: “Truly this world has many obstacles in many ways.
Indeed, for the sake of desire for this [higher state] do they speak or exert themselves; who, having cast this away, would come back here? One should remain right there.”
Ninth section in the fifth lesson.
The fifth lesson is complete.