Kena Upanishad Verse 1.4
Brahman is the power that enables speech but cannot be expressed by speech. The teacher emphasizes that the Absolute is the internal source of expression, not any external object of worship that humans typically conceptualization.
Sanskrit Verse
यद्वाचानभ्युदितं येन वागभ्युद्यते ।
तदेव ब्रह्म त्वं विद्धि नेदं यदिदमुपासते ॥ ४ ॥
Transliteration
yadvācānabhyuditaṃ yena vāgabhyudyate |
tadeva brahma tvaṃ viddhi nedaṃ yadidamupāsate || 4 ||
Translation
What speech does not enlighten, but what enlightens speech, know that alone to be the Brahman, not this which (people) here worship.

Muni's Play