Bhagavad Gita Chapter 18, Verse 50
सिद्धिं प्राप्तो यथा ब्रह्म तथाप्नोति निबोध मे | समासेनैव कौन्तेय निष्ठा ज्ञानस्य या परा ||
siddhiṁ prāpto yathā brahma tathāpnoti nibodha me samāsenaiva kaunteya niṣṭhā jñānasya yā parā
Understand from Me, in summary, O son of Kunti, how one having attained perfection attains Brahman, which is the supreme establishment in knowledge.
Krishna introduces the teaching about transcending the gunas and attaining Brahman. 'Siddhiṁ prāpto yathā brahma tathāpnoti nibodha me'—understand (nibodha) from Me (me), how (yathā) one having attained perfection (siddhim prāptaḥ) attains (āpnoti) Brahman (brahma). 'Samāsenaiva kaunteya niṣṭhā jñānasya yā parā'—in summary (samāsena), O son of Kunti (kaunteya), which is the supreme (parā) establishment (niṣṭhā) in knowledge (jñānasya). This sets up the detailed teaching about how to transcend the gunas and attain the supreme goal—Brahman, the ultimate reality. This is the culmination: after performing one's duty with devotion and renunciation, one attains perfection and ultimately Brahman. This is the path: perfection through duty leads to Brahman, the supreme establishment in knowledge.