Near the end of chapter eighteen, after seventeen chapters of instruction about duty, Krishna tells Arjuna to abandon all duties and come to him alone for refuge, and says he will free him from all wrongs, and not to grieve.
Read against everything that precedes it, the verse is a problem, and every major commentator had to say what it means. In the Sri Vaishnava tradition it is the charama shloka, the final verse, and it is read as the culminating teaching of the entire Gita: surrender, complete and unconditional, which replaces every other means and is available to anyone regardless of qualification. An enormous body of commentary and ritual practice rests on that reading.
Advaita commentary reads it differently. What is abandoned is not the performance of duty but the sense of being the one who performs it, together with any claim on the outcome. Duties continue; ownership of them stops. On this reading the verse restates the position of chapter three rather than overturning it.
A third reading takes the verse as addressed to Arjuna in his particular predicament, a man immobilised by a conflict of obligations who is being told to set the conflict down and act.
The atlas records the point as disputed and does not choose. What is worth noticing is that the disagreement is not marginal: it determines whether the Gita ends by prescribing surrender, by prescribing detached action, or by resolving one man's crisis. Arjuna's own reply is brief. His delusion is destroyed, he has regained recollection, he stands with his doubt gone, and he will do what Krishna says.