Bhagwad Gita
Chapter 18, Verse 9
कार्यमित्येव यत्कर्म नियतं क्रियतेऽर्जुन।सङ्गं त्यक्त्वा फलं चैव स त्यागः सात्त्विको मतः।।18.9।।
But he who performs his prescribed duty only because it ought to be done, and renounces all attachment to the fruit—his renunciation is of the nature of goodness, O Arjuna.