506. For the highly mature souls who seek the supreme sat-chit-ananda in order to free themselves from the scorching heat of birth [and death], it is by the enquiry into only the word ‘Thou’, which [out of the three words ‘That’, ‘Thou’ and ‘Art’] denotes the nature of the individual soul, that the glory of Liberation is attained.
[Sadhu Om: We should remember here Sri Bhagavan’s instruction in verse 32 of 'Ulladu Narpadu' as to what an earnest and sincere disciple should do when he hears the Mahavakya ‘That Thou Art’ from a Guru. As soon as he hears the phrase ‘That Thou Art’, the disciple’s attention should turn to know ‘What am I?’ This is the real aim with which the Mahavakya was revealed. The one important word that stands in the above Mahavakya to turn the disciple’s mind to Self-attention is ‘Thou’. Therefore this verse categorically asserts that out of the three words, ‘Thou’ alone should be taken for scrutiny by a worthy disciple. The following two verses also emphasize the same idea.]
507. Only in order to turn inward the minds of less mature aspirants, which will be favourable for the aforesaid enquiry, [the Vedas] added the other two words ‘That’ [tat] and ‘Art’ [asi] to the word ‘Thou’ [tvam], thereby forming the Mahavakya ‘That Thou Art’ [tat tvam asi]. Thus should you know.
508. Verily the enquiry done within oneself to know the real import denoted by the word ‘Thou’, ‘What is it?’ [‘Who am I?’], is the proper means to know the correct import of the other two words also.