Sankhya Yoga

कर्मण्येवाधिकारस्ते मा फलेषु कदाचन | मा कर्मफलहेतुर्भूर्मा ते सङ्गोऽस्त्वकर्मणि ||

karmaṇy-evādhikāras te mā phaleṣhu kadāchana | mā karma-phala-hetur bhūr mā te saṅgo ’stvakarmani ||

Your right is to work only, but never to its fruits; let not the fruit of action be your motive, nor let your attachment be to inaction.