Chandogya Upanishad 8.10

'He who moves about happy in dreams, he is the Self, this is the immortal, the fearless, this is Brahman.' Then Indra went away satisfied in his heart. But before he had returned to the Devas, he saw this difficulty. Although it is true that that self is not blind, even if the body is blind, nor lame, if the body is lame, though it is true that that self is not rendered faulty by the faults of it (the body),

Nor struck when it (the body) is struck, nor lamed when it is lamed, yet it is as if they struck him (the self) in dreams, as if they chased him. He becomes even conscious, as it were, of pain, and sheds tears. Therefore I see no good in this.

Taking fuel in his hands, he went again as a pupil to Pragâpati. Pragâpati said to him: 'Maghavat, as you went away satisfied in your heart, for what purpose did you come back?' He said: 'Sir, although it is true that that self is not blind even if the body is blind, nor lame, if the body is lame, though it is true that that self is not rendered faulty by the faults of it (the body),

Nor struck when it (the body) is struck, nor lamed when it is lamed, yet it is as if they struck him (the self) in dreams, as if they chased him. He becomes even conscious, as it were, of pain, and sheds tears. Therefore I see no good in this.' 'So it is indeed, Maghavat,' replied Pragâpati; 'but I shall explain him (the true Self) further to you. Live with me another thirty-two years.' He lived with him another thirty-two years. Then Pragâpati said: