Scriptures

Tasmac chastram pramanam te karyakarya-vyavasthitau, jnatva shastra-vidhanoktam karma kartum iharhasi

Therefore, let the scriptures be your authority in determining what should be done and what should not be done. Understanding the scriptural injunctions, you should perform your duties here.

Aphala-kāṅkṣhibhir yajño vidhi-diṣhṭo ya ijyate, yaṣhṭavyam eveti manaḥ samādhāya sa sāttvikaḥ

Sacrifice that is performed as a duty, without desire for reward, according to scriptural injunctions, with a concentrated mind—that is of the nature of goodness.