Thinking about work

Think of your work only when it is being done, not before and not after.
Do not let your mind go back on a work that is finished. It belongs to the past and all rehandling of it is a waste of power.
Do not let your mind labour in anticipation on a work that has to be done. The Power that acts in you will see to it at its own time.
These two habits of the mind belong to a past functioning that the transforming Force is pressing to remove and the physical mind’s persistence in them is the cause of your strain and fatigue. If you can remember to let your mind work only when its action is needed, the strain will lessen and disappear.
This is indeed the transitional movement before the supramental working takes possession of the physical mind and brings into it the spontaneous action of the Light.

Ref: Letters on Yoga – II