Rajas (Sanskrit रजस्, or rajoguna)) is, in the Samkhya school of Hindu philosophy, one of the three gunas. Of these, rajas, is responsible for motion, energy and preservation. and thereby upholds and maintains the activity of the other two gunas, known as sattva and tamas.
The nature of Rajas 
Rajas is the force which promotes or upholds the activity of the other aspects of Nature (prakriti) such as one or more of the following:
If a person or thing tends to be extremely active, excitable, or passionate, that person or thing could be said to have a preponderance of rajas. It is contrasted with the quality of tamas which is the quality of inactivity, darkness, and laziness, and with sattva, which is the quality of purity, clarity, calmness and creativity. Rajas is viewed as being more positive than tamas, and less positive than sattva, except, perhaps, for one who has "transcended the gunas" and achieved equanimity in all fields of relative life.  The rajas stage of life gives a slight clue to the realization of the Absolute Truth in the forms of fine sentiments in philosophy, art and culture with moral and ethical principles, but the mode of sattva is a still higher stage of material quality, which actually helps one in realizing the Absolute Truth.
- Autobiography Of A Yogi, Paramahansa Yogananda, Self Realization Fellowship, 1973, p.22
- Maharishi Mahesh Yogi on the Bhagavad Gita Translation and Commentary, Arkana, 1990 p. 236
- Maharishi Mahesh Yogi on the Bhagavad Gita Translation and Commentary, Arkana, 1990 pp. 221-223