There are three gunas, according to this worldview, that have always been and continue to be present in all things and beings in the world. These three gunas are called: sattva (goodness, calmness, harmonious), rajas (passion, activity, movement), and tamas (ignorance, inertia, laziness).
In the Bhagavad Gita, Lord Krishna tells
Arjuna about the three qualities — sattva, rajas and tamas. Sometimes it
happens that sattva is the dominant quality in a person. In such a case, rajas
and tamas are suppressed. The same can happen in the case of the other two
qualities. And so, if rajas dominates, then sattva and tamas remain subdued. If
tamas dominates, then sattva and rajas are subdued.
When a person’s jnanendriyas reflect pure, unconfused knowledge, then we can conclude that in the case of that person, sattva predominates. A person in whom rajas dominates, exhibits certain characteristics. He is unwilling to spend his money. He will not give even to a deserving man, even though he has the means to give. He indulges in aimless activities. He does things with a view to reaping rewards in future in this life and in the next life too. He is restless. The man with rajas also exhibits sprha — a desire for sense objects. As for the person with tamas predominating, he lacks knowledge. Excess sleep being a characteristic of a person with tamas, how can he be expected to devote time to learning? He is lazy, and lacks concentration. He cannot distinguish between good and bad, right and wrong. What a person will experience in his next birth is determined by which quality is foremost in him at the time of his death.