In plain words
cut anything; however small the task, it still cannot act on itself. Only when it is taken up by someone's hand can it perform those tasks. In just the same way, the intellect too is merely an instrument in the Ātma's hand — it is the Ātma's own instrument.
Prāṇa: Prāṇa itself does not know that it exists during sleep; it has no awareness at all of whether it is breathing or not. It can know the waking, dream and deep-sleep states only each in its own time — it does not recognise waking while it is asleep, nor does it recognise dream while awake. Therefore prāṇa is not the Ātma. In sleep, prāṇa becomes devoid of awareness and is caught in that state. Since the senses lie idle and do not function during sleep, prāṇa appears to lack consciousness. When the master himself is at work, do the servants sit idle?
Now, as for 'I': the word 'I' has two senses. First, Ahaṅkāra — this is also called the body-self, the outer 'I'. Second, the inner Ātma, or pratyagātman — this is the inner 'I'. One who does not know the distinction between these two thinks that the ego alone, the body-self, is 'I' — so people commonly suppose, but this is not true. It is not the Ātma. Since the body is an instrument, and just as any object is something seen, the body-self — that is, the ego — is likewise something seen. This ego does not exist in dream, nor does it exist in deep sleep. 'That which abides through all three states is truth' — so how can something absent in two of the three states be called truth? Reasoning in this way, and finding that none of the senses, the mind, the intellect, or prāṇa is truly the Ātma, you may well begin to wonder: then what is the Ātma? Who indeed is the Ātma?
It has no coming and going; it has neither hands nor feet nor any other limb; no impurity ever touches it. In an atom it is atom-like, in a solid mass it is solid-like, and like space it is present everywhere — and yet it carries no notion of 'I' or 'mine'. As heat is to fire, as light is to the sun, awareness itself is its very nature — that is the Ātma. Free from all connection with grief, anger, the five senses and the rest, that which is supreme bliss — that is the Ātma. In all beings, as the heart within and as consciousness itself, that which alone truly exists