The Blessed Lord said, “O Parthā, that intellect is born of rajas with which one wrongly understands virtue and vice as also what ought to be done and what ought not to be done.
O Parthā, that intellect is born of tamas which, being covered by darkness, considers vice as virtue and verily perceives all things contrary to what they are.
dhrtya yaya dharayate
dhrtih sa partha sattviki – O Parthā, the firmness – dhrtyā that is unfailing – avyabhicārinyā through concentration – yogena, with which – yayā one restrains – dhārayate the mind, vital forces and the organs – manah-prāna-indriya-kriyāh, that firmness – dhrtih is born of sattva.
But O Parthā, the firmness with which one holds on to righteousness, covetable things and wealth, being desirous of their fruits as the occasion for each rises, that firmness is born of rajas.
That firmness is considered to be born of tamas due to which a person with a corrupt intellect does not give up sleep, fear, sorrow, despondency as also sensuality.
[Chapter 18, Slokas 18.31 – 18.35]
Lord Krishna in the above verses elaborates further on the various qualities and attributes of the gunas expressing the importance of sattva, being imbued with faith and engaging in rightful duty, yajnah, dāna and tapah while renouncing the fruits of actions.