The Upanishads, Part 1 (SBE01), by Max Müller, , at sacred-texts.com
1. '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),
2. 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 1.
[paragraph continues] He becomes even conscious, as it were, of pain, and sheds tears. Therefore I see no good in this.
3. 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),
4. 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:
138:1 I have adopted the reading vikkhâyayanti, because it is the most difficult, and therefore explains most easily the various corruptions, or it may be emendations, that have crept into the text. Saṅkara explains vikkhâdayanti by vidrâvayanti, and this shows that he too must have read vikkhâyayanti, for he could not have explained vikkhâdayanti, which means they uncover or they deprive of their clothing, by vidrâvayanti, they drive away. It is true that vikkhâyayanti may be explained in two ways; it may be the causative of khâ, to cut, but this meaning is not very appropriate here, p. 139 and quite inadmissible in another passage where vikkhâyayanti occurs, whereas, if derived from vikh (ὀίχομαι) in a causative sense, Saṅkara could hardly have chosen a better explanation than vidrâvayanti, they make run away. The root vikh, vikkhâyayati is recognised in Pânini III, 1, 28, and in the Dhâtupâtha 28, 129, but it has hitherto been met with in this passage only, and in Brihadâranyaka, Up. IV, 3, 20. Here also the author speaks of a man who imagines that people kill him or do him violence, or that an elephant chases him or that he falls into a pit. Here we have hastîva vikkhâyayati, and Saṅkara, at least as printed by Dr. Roer, explains this by vikkhâpayati, vikkhâdayati, vidrâvayati; dhâvatîty arthah. Much better is Dvivedaganga's commentary, as published by Dr. Weber, Satap. Brâhm. p. 1145, Kadâkid enam hastî vikkhâyayatîva vidrâvayatîva; vikha gatau, gupûdhûpavikhipanipanibhya âya iti (Pân. III, 1, 28) svârtha âyapratyayah. In the Dictionary of Boehtlingk and Roth the derivation from khâ, to cut, is preferred; see Nachträge, s. v. khâ.