Purity and Simplicity of the Vital in Yoga

You must not try to get experiences; you are not yet ready for them; instead of the right experience something abnormal comes. You must get your vital purified and calm so that these movements may not come. Nothing abnormal like not sleeping, not eating – all that is the vital trying to do extraordinary things so as to imagine it is going fast and doing high sadhana. A pure, simple, quiet, well-balanced vital is necessary for this Yoga.

Ref: Letters on Yoga Vol. III