Calm, discrimination, detachment (but not indifference) are all very important, for their opposites impede very much the transforming action. Intensity of aspiration should be there, but it must go along with these. No hurry, no inertia—neither rajasic over-eagerness nor tamasic discouragement—a steady and persistent but quiet call and working. No snatching or clutching at realisation, but allowing realisation to come from within and above and observing accurately its field, its nature, its limits.
Ref: Letters on Yoga Vol. III