Shri Shankara Acharya’s Vakyavritti Verse 38
“This great sentence does not imply the coexistence of the individual and the cosmic Self, nor does it mean that a particular aspect of Brahman is the Self. According to the wise, it affirms the basic identity of ‘That’ and ‘Thou’ without any reservation or condition”.
The dualist philosophers are responsible for many distortions of the holy dictum. Some have assumed wrongly, through misinterpretation, that both the Self of man and the divine Self exist together, just as the light of a candle burning by day co-exists with the sunlight.
Others hold that the sentence expresses a particular characteristic of the individual Self but not its identity with Brahman: they say for instance, that the Self of man is divine but not the same as God.
Ramanuja, Madhva and Nimbarka have offered their own interpretations of the great sentence on these and similar lines, but wise students do not accept them.
In fact the meaning is the whole and absolute identity of ‘That’ and ‘Thou’ (Brahman and Jiva).
When the Yogi meditates on the identity of his Self with the divine Self as the one and only reality which is non-dual in character, the truth is revealed to him if he has been a true disciple to his Guru.