Chapter 18 · Liberation through Renunciation · Krishna said
Bhagavad Gita 18.50 — Reaching Brahman
सिद्धिं प्राप्तो यथा ब्रह्म तथाप्नोति निबोध मे। समासेनैव कौन्तेय निष्ठा ज्ञानस्य या परा ॥
siddhiṃ prāpto yathā brahma tathāpnoti nibodha me | samāsenaiva kaunteya niṣṭhā jñānasya yā parā ||
Meaning
O Arjuna, hear from Me briefly how one who has reached perfection attains Brahman, the highest state of knowledge.