In plain words
That is exactly why they held Prajñānaṃ Brahma to be the chief essence within the Veda.
In the four Vedas the chief sūtras are four. They are Tattvamasi, Prajñānaṃ Brahma, Ayamātmā Brahma, Ahaṃ Brahmāsmi. All these sūtras, full of endless meanings, flow within man himself, inherent in him. If man wants to know this, he need not go outside to know it. He need not know it through books. Everything is in himself. He forgets the whole of what is in himself, offers his all to something he thinks is outside, and in the end falls prey to despair and dejection. What he lost is in one place; the searching is in another. How will that thing be found? So he falls prey to despair. He must go where he lost it, and search there. Everything is in himself. So he must search in himself. Only then will this divine, radiant Prajñā come to him. In this very word akṣara everything is contained. That is, the oneness of the two, the transient and the eternal, is itself this akṣara. Here let us divide it into two parts. A, kṣara. A: what is endless. What is immeasurable. What is beyond proof. That itself is full of Ānanda. That itself is the Ātma. That itself is the eternal. Next, kṣara. What is transient. What is unreal. What has no measure. Kṣara means what perishes. The a means what never perishes. The very joining of these two is akṣaraṃ. The oneness of the two, the imperishable and the perishable, is itself akṣaraṃ. But we think it is only one word. No, no. We must divide it into two words. The transient world exists in the eternal Paramātma itself. The world cannot exist apart from the Paramātma. The Paramātma cannot exist apart from the world. The devotee creates God. God creates the devotee. People think God alone creates all people, all living beings. No, no. The devotee too creates God for himself through the wealth of his sādhana: that is what is called sākṣātkāra. Where does this sākṣātkāra come from? Only through the devotee's own surges of feeling does he understand it. Sākṣāt ākāra, the form made manifest: that is sākṣātkāra. That is exactly why the creator of God is the devotee himself. The creator of the devotee is God Himself. So today, because the devotee cannot recognise that truth, he tries to search for God, asking, ‘Where, where?’ What ignorance! Where can one search for God, who fills everything? So to think that you are searching for God is a delusion. God Himself is searching for the true devotee. Because where the true devotee is cannot be seen. This power of inquiry has been doing this. Tyāgarāja recognised exactly this, beautifully: