Bhagwad Gita
Chapter 17, Verse 11
अफलाकाङ्क्षिभिर्यज्ञो विधिदृष्टो य इज्यते।यष्टव्यमेवेति मनः समाधाय स सात्त्विकः।।17.11।।
Of sacrifices, that sacrifice performed according to duty and to scriptural rules, and with no expectation of reward, is of the nature of goodness.