Bhagavad Gita 18.59

If you in your vanity think of avoiding this fight, your will shall not be fulfilled, for Nature herself will compel you.

यदहङ्कारमाश्रित्य न योत्स्य इति मन्यसे।मिथ्यैष व्यवसायस्ते प्रकृतिस्त्वां नियोक्ष्यति॥

yadahaṅkāramāśritya na yotsya iti manyase|mithyaiṣa vyavasāyaste prakṛtistvāṃ niyokṣyati||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).