The one whose happiness is within, whose delight is within, and whose light is likewise within — that yogi, having become Brahman, attains the nirvana of Brahman.
Explanation
Krishna continues describing the person who has mastered the surge of desire and anger. Such a yogi finds joy and illumination (jyoti) within, not in outside things, and so becomes one with Brahman, the ultimate reality, reaching Brahman-nirvana (brahmanirvāṇa), the 'extinguishing' of bondage in it. Advaita readers take this as realizing the self's identity with Brahman, while devotional traditions stress a liberation that remains in relationship with the Lord.