'That which is that subtile essence, in it all that exists has its self. It is the True. It is the Self, and thou, O Svetaketu, art it.' 'Please, Sir, inform me still more,' said the son. 'Be it so, my child,' the father replied.

In plain words: The father repeats: one fine, hidden essence is the true self of everything. It is the True, it is the Self, and 'you are that, Svetaketu.' Svetaketu asks to learn more, and his father agrees.