मयि सर्वाणि कर्माणि संन्यस्याध्यात्मचेतसा।निराशीर्निर्ममो भूत्वा युध्यस्व विगतज्वरः॥
mayi sarvāṇi karmāṇi sannyasyādhyātma-cetasānirāśīr nirmamo bhūtvā yudhyasva vigata-jvaraḥ
Word by word
The verse says
Hand all your actions over to me, with your mind on what is deepest. Let go of expecting anything, let go of mine, and fight - without the fever.
In plain words
The chapter's instruction, finally given whole. Four things at once.
Give the actions to me. Drop expectation. Drop mine. Then fight.
And the last word, which is the most human in the verse: vigata-jvaraḥ - without fever.
Where you've felt this · in grief
You sit up with a friend through the worst night of his life, and at some point you stop trying to fix it. You are still completely there - still listening, still handing him water. What has gone is the heat under your own hands.
Going deeper
Vigata-jvara - fever gone. It is a medical word, and the Gita keeps reaching for the physician's vocabulary rather than the judge's. Chapter 2 did the same, describing the settled state as the one without illness.
What is the fever? Not the fighting. Not even the grief. It is the hot agitation that comes from holding an outcome you cannot control - the thing that had Arjuna shaking and dropping his bow in the first chapter.
Nirmama - without mine - is the same word that closes Chapter 2's portrait at 2.71, and it points back to the possessive pronouns that opened the whole book.
And mayi sannyasya - handing over into me. This is the second time the chapter has quietly made Krishna the method rather than the argument, after 2.61. The path of action has just acquired a direction.
Note the order of operations. The fighting comes last, and it comes after everything else has been set down. Krishna is not asking for a harder push. He is asking for the same act with the weight taken off it.