Katha Upanishad Verse 2.3.10

The highest state of spiritual attainment is reached when the five organs of perception (the senses) and the mind become still, and the intellect ceases its restless activity. This profound stillness is the gateway to the Absolute.

Sanskrit Verse

यदा पञ्चावतिष्ठन्ते ज्ञानानि मनसा सह ।
बुद्धिश्च न विचेष्टते तामाहुः परमां गतिम् ॥ १० ॥

Transliteration

yadā pañcāvatiṣṭhante jñānāni manasā saha |
buddhiśca na viceṣṭate tāmāhuḥ paramāṃ gatim || 10 ||

Translation

When the five organs of perception become still, together with the mind, and the intellect ceases to be active: that is called the highest state.