18.30 The intellect which knows the path of work and renunciation, what ought to be done and what ought not to be done, fear and fearlessness, bondage and liberation that intellect is Sattvic (pure), O Arjuna.
प्रवृत्तिं च निवृत्तिं च कार्याकार्ये भयाभये |
बन्धं मोक्षं च या वेत्ति बुद्धिः सा पार्थ सात्त्विकी ||१८-३०||
18.31 That, by which one wrongly understands Dharma and Adharma and also what ought to be done and what ought not to be done that intellect, O Arjuna, is Rajasic (passionate).
यया धर्ममधर्मं च कार्यं चाकार्यमेव च |
अयथावत्प्रजानाति बुद्धिः सा पार्थ राजसी ||१८-३१||
18.33 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 Sattvic (pure).
18.34 But that, O Arjuna, by which, on account of attachment and desire for reward, one holds fast to Dharma (duty), enjoyment of pleasures and earning of wealth that firmness, O Arjuna, is Rajasic (passionate).
18.37 That which is like poison at first but in the end like nectar that happiness is declared to be Sattvic, born of the purity of one's own mind due to Self-realisation.