In plain words
The Guru is the very embodiment of the essence of the four Mahāvākyas, ‘Prajñānaṃ brahma’, ‘Ahaṃ brahmāsmi’, ‘Tattvamasi’ and ‘Ayamātmā brahma’
‘Tattvamasyādi lakṣyaṃ.’ What are these tattvas? There are four Mahāvākyas. One is ‘Prajñānaṃ brahma.’ This came from the Ṛgveda. It is the essence of the Ṛgveda. ‘Ahaṃ brahmāsmi’: this is the essence of the Yajurveda. ‘Tattvamasi’: this is the essence of the Sāmaveda. ‘Ayamātma brahma’: this is the essence of the Atharvaṇaveda. In this way the Upaniṣads divided the essence of the four Vedas into four Mahāvākyas. These four Mahāvākyas have gone on establishing the one divinity. They show different paths, yet they set out the goal as only one. The very first is ‘Prajñānaṃ brahma.’ What does this prajñā mean? ‘This fellow is very brilliant!’ we keep saying. Today we call cleverness prajñā. No, no. This is not prajñā. Where is this prajñā? In the body, in the senses, in the Manas, in the Buddhi, in the antaḥkaraṇa, in Ahaṅkāra: this prajñā is everywhere. Prajñā is in all that breathes, in all beings, in the moving and the unmoving. This very thing they have called Constant Integrated Awareness. What does Awareness mean? Knowing. Knowing what? Knowing this much and that much? No, no: knowing all.
That is full; this is full; from the full the full arises. Taking the full from the full, the full alone remains.
We must know fully. It is recognising the principle that is in the moving and the unmoving. In this ‘Prajñānaṃ brahma’, prajñā and Brahma are words of equal meaning! Some scholars explain that prajñāna itself is Brahman. This prajñāna and Brahman are not different. What does Brahma mean? He who pervades everything. ‘Brahma’ is the name of the very twoness through which the Brahman principle has spread abroad and made itself known as the form of everything. This whole world is nothing but the form of Brahman!