This is a brief sub-gloss. For a fuller reading of this verse, see Madhusūdana, Śaṅkara, or Rāmānuja above.
If, taking refuge in egotism, you think, you settle the conviction, 'I will not fight', this resolve of yours is in vain, since your own nature, the nature of a kshatriya, will compel you.
Contemporary English rendering of the Sanskrit bhāṣya, pending scholar review.