MUṆḌAKA UPANISHAD · 3.2.3

नायमात्मा प्रवचनेन लभ्यो
न मेधया न बहुना श्रुतेन ।
यमेवैष वृणुते तेन लभ्यस्तस्यैष आत्मा विवृणुते तनूं स्वाम् ॥ ३॥

nāyamātmā pravacanena labhyo
na medhayā na bahunā śrutena ।
yamevaiṣa vṛṇute tena labhyastasyaiṣa ātmā vivṛṇute tanūṃ svām ॥ 3॥

This Self is not won by exegesis, nor by brain-power, nor by much learning of Scripture. Only by him whom It chooses can It be won; to him this Self unveils its own body.