BG Chap 14 - Results of actions in the various modes
The result of work in sattva is pure happiness without distress. While developing our Kṛṣṇa consciousness, we must attempt to perform our services in at least the mode of goodness, otherwise passion and ignorance would adversely affect our consciousness. By hearing about Kṛṣṇa regularly, we can become free from rajas and tamas. One purified from these base modes is no longer attacked by greediness and passion, and thus becomes happy. This happiness is devoid of sorrow, illusion and impurity.
The result of work in rajas is a little happiness with abundance of grief. There is a mixture of piety and sin in the mode of passion, and thus the result is mixed happiness and distress. The result of work on tamas such as violent actions is grief alone, in which one’s awareness is totally covered by ignorance.