Mahabharata 8.11.21

अन्योन्यस्य वधे यत्नं चक्रतुस्तौ महारथौईषतुर्विरथं चैव कर्तुमन्योन्यमाहवे

anyonyasya vadhe yatnaṃ cakratustau mahārathauīṣaturvirathaṃ caiva kartumanyonyamāhave

Our plain-language meaning of this verse is waiting for scholar review.