yo 'ntaḥ-sukho 'ntar-ārāmas
tathāntar-jyotir eva yaḥ
sa yogī brahma-nirvāṇaṁ
brahma-bhūto 'dhigacchati
yaḥ - one who; antaḥ-sukhaḥ - happy from within; antaḥ-ārāmaḥ - actively enjoying within; tathā - as well as; antaḥ-jyotiḥ - aiming within; eva - certainly; yaḥ - anyone; saḥ - he; yogī - a mystic; brahma-nirvāṇam - liberation in the Supreme; brahma-bhūtaḥ - being self-realized; adhigacchati - attains.
Unless one is able to relish happiness from within, how can one retire from the external engagements meant for deriving superficial happiness? A liberated person enjoys happiness by factual experience. He can, therefore, sit silently at any place and enjoy the activities of life from within. Such a liberated person no longer desires external material happiness. This state is called brahma-bhūta, attaining which one is assured of going back to Godhead, back to home.