Verse 21

तिर्यगूर्ध्वमधस्ताच्च व्यापको महिमात्मनः ।सर्वमात्मेति तेनान्तर्निश्चयेन न बध्यते

In plain words

Sideways, above, and below, the greatness of the ātman pervades all. 'All is ātman' — by that niścaya held within, one is not bound.