A compelling companion of happiness; its presence is never welcome. Yet if there was no sorrow happiness alone may be hell or almost that.
The greatest gain that you can draw from pain, is the lessons that you will learn during the spell of sorrow. You review you bad actions; you remember God. You draw inferences, you think of improving your ways. You curb your ego and stretch out for help. You develop, at best your courage to face and put impending difficulties to rest.
