FROM SWAMI SIVANANDA'S TEACHINGS
Being a great force, thought carries tremendous power. It becomes a matter of great moment to know how to use this power in the highest possible way and to the greatest possible effect. This can best be done by the practice of meditation. Careful reflection will show you that the entire universe is in reality a projection of the human mind. Purification and control of the mind is the central aim of all yogas. The mind in itself is but a record of impressions that keep expressing ceaselessly as impulses and thoughts. Thought impels you to action; activity creates fresh impressions in the mind. Yoga strikes at the very root of this vicious circle by effectively checking, controlling and stopping the root function of the mind i.e. thought. When thought is transcended, intuition functions and self-knowledge supervenes.