Shanti Parva 203.3

There is Rajas, there is Tamas, and there is Satva the third. There arc again three conditions of the understanding, viz., waking, dreaming, and sound sleep. The Soul perceives the pleasures and pains, which are all contradictory, of those states, and which partake of the nature of the three-fold qualities first mentioned. The Soul enters the senses like the wind entering the fire in piece of wood.