Penetration of our mind is our goal, but in the beginning to set things in motion, there is no substitute for sweat. ~BKS Iyengar
In Light on the Yoga Sutras of Patanjali, Mr Iyengar designed a table* in which he illustrates the evolution of citta (consciousness) regarding its 3 component states (gunas): sattva (luminosity), rajas (vibrancy), and tamas (inertia). According to his chart, when we first begin practicing yoga, the consciousness is dull, dark, and inert, dominated by the quality tamas. As we apply effort to shifting the consciousness, the quality of rajas becomes prevalent characterized by movement and effort, a fire within. With continued practice, the consciousness becomes light and peaceful, sattva, until eventually the consciousness transcends these three qualities of nature.
So what I take away from Mr Iyengar’s presentation is that if we ever want to attain a sattvic (peaceful) or transcendent state, we have to traverse the others first: tamas (darkness) and rajas (fire). There isn’t a shortcut that will take us directly from darkness to light, we have to go through the fire… which may involve a little perspiration.
*Table 8 in his commentary on Sutra II.18 on the gunas