Verse 2.225

Sanskrit text and transliteration:

ज्ञातास्मीत्यभिमानाद्धि चेष्टते ज्ञानकर्मणि ।
मन्ताऽस्मीति ततो मोहात्कुरुते मानसीः क्रियाः ॥ २२५ ॥

jñātāsmītyabhimānāddhi ceṣṭate jñānakarmaṇi |
mantā'smīti tato mohātkurute mānasīḥ kriyāḥ || 225 ||

English translation of verse 2.225:

Owing to the conceit “I am the knower”, the jīva, indeed, performs the acts of cognition. Again, on account of the delusion "I am the thinker”, he does all mental activities.

Notes:

The mechanism of identification of the Self with the two bodies (śarīra-dvaya), gross as well as subtle, takes place at different levels. It has already been stated that the subtle body is composed of three sheaths—the sheath of self-consciousness (vijñānamaya-kośa), the sheath of consciousness (manomaya-kośa), and the sheath of vitality (prāṇamaya-kośa).

While buddhi along with the organs of knowledge constitute the sheath of self-consciousness, manas taken with the same organs of knowledge constitutes the sheath of consciousness. The Self or the "I” is different from the intellect (buddhi) and the mind (manas). If it is identified with any of them, it is a case of superimposition (adhyāsa) due to ignorance. On account of the erroneous identification with buddhi, the Self looks upon itself as a knower, engages in the acts of cognition, considers itself as the agent and the enjoyer of the fruits of actions. In the same way, its identification with manas makes it think that it performs the various mental operations such as upāsanā. So the Self must be differentiated from the vijñānamaya-kośa and the manomaya-kośa.