The raw power generated by an electricity power plant is far greater than any single house can sustain. Thus, the utility company utilizes step-down transformers to systematically bring the power down to a level that the homes and the wiring to the homes can sustain.
A similar principle is at work with regard to the universal forces and the ability of any individual to receive and hold those forces. This is the reason that much of the work done in any yogic practice is to prepare the being to receive and utilize the force that descends.
Raja Yoga provides a great example. The first two steps, yama and niyama include various vital purifications and control and management of the vital forces active in the being, such as non injury, non stealing, truthfulness, contentment, etc. If any of these vital predilections is active, it can either misuse the energy coming in or waste it without accomplishing the spiritual objective. The next stage includes asana, in terms of maintaining a solid physical frame and capacity to hold and move energy. While this is mostly associated with the physical frame, actually the term asana can signify the entire being at all its levels. The goal of a solid ‘seat’ therefore is to have a framework, physical, vital and mental, that can hold the yogic forces when they enter and are activated in the being. The next step is pranayama which is the management of the prana or the vital force that activates and operates within the physical body. The prana is also the link between the external forces and the physical frame, and is usually controlled through management of the breathing process. There is a direct link also between the management of the thoughts and the management of the breath, so it is an essential step to gain control of the breath, purify the ‘channels’ through which the various forms of prana move, and bring the thoughts also under control, eventually leading to a quieting of the mental process. It is only after these 4 preliminary stages are accomplished that Raja Yoga moves on to the deeper practices that bring direct connection to the spiritual reality and the forces that are at work at those levels.
A disciple asks: “Sweet Mother, do the universal vital forces have any limits?”
The Mother answers: “I don’t think that forces have a limit, because in comparison with us they are certainly unlimited. But it’s our capacity of reception that is limited. We cannot absorb them beyond a certain measure, and then we must keep a balance between the expenditure and the capacity to receive. If one spends suddenly in a kind of impulse — for example, in an impulsive movement — if one spends much more than one has received, one needs a brief moment of concentration, calm, receptivity to absorb universal forces. You must put yourself in a certain condition to receive them; and then, they last for a certain time, and once you have spent them you must begin again to receive them. It is in this sense that there are limits. It isn’t the forces that are limited, it is the receptivity.”
Sri Aurobindo and the Mother, The Hidden Forces of Life, Ch. 4 Cosmic and Universal Forces, pg 96
Sri Aurobindo Studies 