Sri Aurobindo
Letters of Sri Aurobindo
04. The Foundation of Sadhana
There can be no firm foundation in sadhana without equality, samatā. Whatever the unpleasantness of circumstances, however 
disagreeable the conduct of others, you must learn to receive them with a perfect calm and without any disturbing reaction. These things are the test of equality. It is easy to be calm and equal when things go well and people and circumstances are pleasant; it is when they are the opposite that the completeness of the calm, peace, equality can be tested, reinforced, made perfect.