On Shrimad Bhagwad Gita: What does it mean to ‘see the self by the self’?

The following is an excerpt from a samvaad (dialogue) session with Acharya Prashant.

यत्रोपरमते चित्तं निरुद्धं योगसेवया ।

यत्र चैवात्मनात्मानं पश्यन्नात्मनि तुष्यति ।।

yatroparamate chittaṁ niruddhaṁ yoga-sevayā