Gita Chapter 18.31 to 18.35

Yayaa dharmamadharmam cha kaaryam chaakaaryameva cha;
Ayathaavat prajaanaati buddhih saa paartha raajasee.
31. That by which one incorrectly understands Dharma and Adharma, and also what ought to be done and what ought not to be done—that intellect, O Arjuna, is Rajasic!
COMMENTARY: That which is ordained in the scriptures is Dharma. That which hurls you into the abyss of ignorance is Adharma. The Rajasic intellect is not able to distinguish between righteous and unrighteous actions.

Adharmam dharmamiti yaa manyate tamasaavritaa;
Sarvaarthaan vipareetaamshcha buddhih saa paartha taamasee.
32. That which, enveloped in darkness, views Adharma as Dharma and all things perverted—that intellect, O Arjuna, is called Tamasic!

Dhrityaa yayaa dhaarayate manah praanendriyakriyaah;
Yogenaavyabhichaarinyaa dhritih saa paartha saattwikee.
33. The unwavering firmness by which, through Yoga, the functions of the mind, the life-force and the senses are restrained—that firmness, O Arjuna, is Sattwic!

Yayaa tu dharmakaamaarthaan dhrityaa dhaarayate’rjuna;
Prasangena phalaakaangkshee dhritih saa paartha raajasee.
34. But that firmness, O Arjuna, by which, on account of attachment and desire for reward, one holds fast to Dharma, enjoyment of pleasures and earning of wealth—that firmness, O Arjuna, is Rajasic!

Yayaa swapnam bhayam shokam vishaadam madameva cha;
Na vimunchati durmedhaa dhritih saa paartha taamasee.
35. That by which a stupid man does not abandon sleep, fear, grief, despair and also conceit—that firmness, O Arjuna, is Tamasic!

Gita Chapter 18.06 to 18.10

Etaanyapi tu karmaani sangam tyaktwaa phalaani cha;
Kartavyaaneeti me paartha nishchitam matamuttamam.
6. But even these actions should be performed leaving aside attachment and the desire for rewards, O Arjuna! This is My certain and best conviction.
COMMENTARY: This is a summary of the doctrine of Karma Yoga already enunciated before. The defect in Karma is not in the action itself but in attachment and expectation of a reward.

Niyatasya tu sannyaasah karmano nopapadyate;
Mohaattasya parityaagas taamasah parikeertitah.
7. Verily, the renunciation of obligatory action is improper; the abandonment of the same from delusion is declared to be Tamasic.

Duhkhamityeva yat karma kaayakleshabhayaat tyajet;
Sa kritwaa raajasam tyaagam naiva tyaagaphalam labhet.
8. He who abandons action on account of the fear of bodily trouble (because it is painful), he does not obtain the merit of renunciation by doing such Rajasic renunciation.

Kaaryamityeva yatkarma niyatam kriyate’rjuna;
Sangam tyaktwaa phalam chaiva sa tyaagah saattwiko matah.
9. Whatever obligatory action is done, O Arjuna, merely because it ought to be done, abandoning attachment and also the desire for reward, that renunciation is regarded as Sattwic!

Na dweshtyakushalam karma kushale naanushajjate;
Tyaagee sattwasamaavishto medhaavee cchinnasamshayah.
10. The man of renunciation, pervaded by purity, intelligent and with his doubts cut asunder, does not hate a disagreeable work nor is he attached to an agreeable one.