The three forces

In every man there are three forces. Sometimes Tamas prevails. We become lazy, we cannot move, we are inactive, bound down by certain ideas or by mere dullness. At other times activity prevails, and at still other times that calm balancing of both. Again, in different men, one of these forces is generally predominant. The characteristic of one man is inactivity, dullness and laziness; that of another, activity, power, manifestation of energy; and still in another we find the sweetness, calmness, and gentleness, which are due to the balancing of both action and inaction. So in all the creation - in animals, plants, and humans - we find the more or less typical manifestation of all these different forces.
--Ideas of Swami Vivekananda
(Part of Karma-yoga)