Kaṭha Upaniṣad 2.23

2.23

nāyam ātmā pravacanena labhyo na medhayā na bahunā śrutena /
yam evaiṣa vṛṇute tena labhyas tasyaiṣa ātmā vivṛṇute tanūṃ svām //

23. This Soul (Ātman) is not to be obtained by instruction,
Nor by intellect, nor by much learning.
He is to be obtained only by the one whom He chooses;
To such a one that Soul (Ātman) reveals his own person (_tanūṁ svām_).
24. Not he who has not ceased from bad conduct,
Not he who is not tranquil, not he who is not composed,
Not he who is not of peaceful mind
Can obtain Him by intelligence (_prajñā_).