The Gītā begins with a blind king’s question. Dhṛtarāṣṭra asks what happened on the field of dharma. Six hundred and eighty-seven verses later, near the very end, Kṛṣṇa gives Arjuna a different instruction: relinquish all dharmas, and take refuge in Him alone. The book that opens on dharma closes by asking you to set it down. Not to stop doing right. To stop carrying it alone.
The verses
BHAGAVAD GĪTĀ · 1.1धृतराष्ट्र उवाच
धर्मक्षेत्रे कुरुक्षेत्रे समवेता युयुत्सवः।
मामकाः पाण्डवाश्चैव किमकुर्वत सञ्जय।।
dhṛtarāśtra uvāca
dharma-kṣetre kuru-kṣetre samavetā yuyutsavaḥ
māmakāḥ pāṇḍavāścaiva kimakurvata sañjaya
Dhṛtarāṣṭra said: “O Sanjaya, what did my people and the Pāṇḍavas do, gathered together on the holy field of Kurukshetra, eager for battle?”
BHAGAVAD GĪTĀ · 18.66सर्वधर्मान्परित्यज्य मामेकं शरणं व्रज।अहं त्वा सर्वपापेभ्यो मोक्षयिष्यामि मा शुचः।।
sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja
ahaṁ tvāṁ sarva-pāpebhyo mokṣayiṣyāmi mā śucaḥ
Relinquishing all Dharmas completely, seek Me alone for refuge. I will release you from all sins; grieve not.
Going deeper
The Gītā begins with a question and ends its teaching with an instruction. 1.1 is Dhṛtarāṣṭra's question about what his people and the Pāṇḍavas did on the holy field of Kurukṣetra. 1.2 is where Sañjaya's answer starts. Near the end, 18.65 asks Arjuna to fix his mind on Kṛṣṇa, be his devotee, worship him and bow to him. Then 18.66 gives the instruction the story is about: give up all dharmas, take refuge in me alone, I will release you from all sins, do not grieve. 18.67 limits to whom it should be told. The story reads this as a close that mirrors the opening: a book that begins on dharma ends by asking you to set it down, which, it says, is not to stop doing right but to stop carrying it alone. Read both ends at chapter 1 and chapter 18, and what the Gītā says about dharma.