नायमात्मा प्रवचनेन लभ्यो न मेधया न बहुना श्रुतेन ।
यमेवैष वृणुते तेन लभ्यस्तस्यैष आत्मा विवृणुते तनूँ स्वाम् ॥ २३ ॥

nāyamātmā pravacanena labhyo na medhayā na bahunā śrutena |
yamevaiṣa vṛṇute tena labhyastasyaiṣa ātmā vivṛṇute tanūm̐ svām || 23 ||

23. This atman is not to be attained by a study of the Vedas, nor by intelligence, nor by much hearing, but the atman can be attained, only by him who seeks to know it. To him, this atman reveals its true nature.

Shankara’s Commentary:

This text says that though this atman is hard to know, still he can certainly be known well by proper means. This atman is not attainable by the study of many Vedas, or by intelligence, i.e., a retentive memory of the import of books, or by any amount of mere learning. By what then can he be attained is explained. That atman (self) whom the neophyte seeks, by the same self, i.e., by the seeker, can the atman be known. The meaning is that, of one who seeks only the atman, being free from desire, the atman is attained by the atman alone. How it is attained is explained. To the man who seeks the atman, the atman reveals its real form, i.e., its own true nature.