6.7 Of him whose self is conered, i.e., whose mind is conered, whose mind is free from fluctuations and who is very calm, 'the great self' becomes well secured, i.e., exceedingly well secured in connection with heat and cold, pleasure and pain, and honour and dishonour.

Here the individual self (Pratyagatman) is called 'the great self' (Paramatman), as the context justifies this only. It can also be called 'great', because it is at a higher stage relatively to previous successive stages. Or the word may be construed as follows:  The self is secured greatly - Atma parma samahitah. [In any case it should not be taken as the Supreme Being].