BG 17.11
अफलाकाङ्क्षिभिर्यज्ञो विधिदृष्टो य इज्यते
यष्टव्यमेवेति मनः समाधाय स सात्त्विकः
aphalākāṅkṣibhiryajño vidhidṛṣṭo ya ijyate
yaṣṭavyameveti manaḥ samādhāya sa sāttvikaḥ
TRANSLATION
The sacrifice (worship) marked by Sattva is what is offered by those desiring no fruit, and having the conviction that it should be performed as enjoined in the Shastras.
PURPORT
That sacrifice is marked by Sattva which is offered by those desiring no fruits, with the ‘conviction’, i.e., with the idea that it ought to be performed or that it should be offered for its own sake as worship of the Lord as enjoined in the injunctions of the Shastras, i.e., with hymns, right materials and proper rituals.