18:62 – The deluded one often shows aversion for his possessions. But there is neither attraction nor aversion for one whom attachment to the body has vanished.
The “one whom attachment to the body has vanished” is the wise one with self-knowledge who no longer identifies with the body (and by extension, the mind). They only identify with the self and as such, attraction and aversion—which only pertain to the body-mind—no longer apply to them.
Calling the unenlightened “deluded”—while true—is a bit uncharitable insofar as no one causes their own self-ignorance. Everyone is simply born into it through no fault of their own.
18:63 – The mind of the deluded one is always attached to thinking and not thinking. But the one who abides in the self does not think even when thinking of the thinkable.
“The one abides in the self” doesn’t think, even when the mind is thinking because they know they’re not the mind—they’re the self, ever-free of thought. But the “deluded one” (one without self-knowledge) is always attached to thinking and not-thinking because they’re still identified with the mind.
18:64 – The wise one who has no motive in all his actions, who moves like a child and is pure, has no attachment even to the work that is being done by him.
The wise one, as the self, has no motives although their mind most likely does. Whether they move like a child or not is irrelevant because they aren’t the body-mind. As the self they have no attachment to work (action) because the self is free of both action and attachment.
18:65 – Blessed indeed is that knower of self, who has transcended the mind, and who, even though seeing, hearing, touching, smelling, or eating, is the same under all conditions.
You “transcend” the mind by knowing that as the self, you’re never affected by the mind. Then you understand that you’re always the changeless self regardless of what’s appearing in the mind, be it seeing, hearing, touching, smelling, eating or anything else.
18:66 – Where is samsara, where is appearance (of the world)? Where is achievement or the striving to achieve for one with steadfast knowledge who is unchanging and all-pervasive like space?
Only the self exists. When this known, the reality of the world and the suffering it causes (samsara) are negated. Achievement and the striving to achieve are also negated, seeing as they’re part and parcel of the unreal world.
“The one with steadfast knowledge” is “unchanging and all-pervasive like space” because they know directly and without a doubt, “I am the changeless, all-pervasive self.”
Space is a great metaphor for the self because it’s everywhere, indivisible and unaffected by the objects that appear in it. But really speaking, it’s more accurate to say that space is unchanging and all-pervasive like the self, and not the other way around because space is an illusion that depends on the self for its seeming existence.