MUṆḌAKA UPANISHAD · 3.1.4

प्राणो ह्येष यः सर्वभूतैर्विभाति
विजानन् विद्वान् भवते नातिवादी ।
आत्मक्रीड आत्मरतिः क्रियावानेष ब्रह्मविदां वरिष्ठः ॥ ४॥

prāṇo hyeṣa yaḥ sarvabhūtairvibhāti
vijānan vidvān bhavate nātivādī ।
ātmakrīḍa ātmaratiḥ kriyāvāneṣa brahmavidāṃ variṣṭhaḥ ॥ 4॥

This is the life in things that shines manifested by all these beings; a man of knowledge coming wholly to know this, draws back from creeds and too much disputings. In the Self his delight, at play in the Self, doing works, — the best is he among the knowers of the Eternal.

Sri Aurobindo · CWSA 18, p. 142