Wisdom from the Bhagavad Gita 62

29. Hear you the triple distinction of intellect and fortitude, according to the Gunas, as I declare them exhaustively and severally, O Dhananjaya. 

30. That which knows the paths of work and renunciation, right and wrong action, fear and fearlessness, bondage and liberation, that intellect, O Pârtha, is Sâttvika. 

31. That which has a distorted apprehension of Dharma and its opposite and also of right action and its opposite, that intellect, O Pârtha, is Râjasika. 

32. That which enveloped in darkness regards Adharma as Dharma and views all things in a perverted light, that intellect, O Pârtha, is Tâmasika. 

33. The fortitude by which the functions of the mind, the Prâna and the senses, O Pârtha, are regulated, that fortitude, unswerving through Yoga, is Sâttvika. 

34. But the fortitude by which one regulates one's mind to Dharma, desire and wealth, desirous of the fruit of each from attachment, that fortitude, O Pârtha, is Râjasika. 

35. That by which a stupid man does not give up sleep, fear, grief, despondency and also overweening conceit, that fortitude, O Pârtha, is Tâmasika. 

36. And now hear from Me, O bull of the Bhâratas, of the threefold happiness. That happiness which one learns to enjoy by habit, and by which one comes to the end of pain. 

37. That which is like poison at first, but like nectar at the end; that happiness is declared to be Sâttvika, born of the translucence of intellect due to Self-realization. 

38. That which arises from the contact of object with sense, at first like nectar, but at the end like poison, that happiness is declared to be Râjasika. 

39. That happiness which begins and results in self-delusion arising from sleep, indolence and miscomprehension, that is declared to be Tâmasika. 

—Bhagavad Gita, 18:29-39