It is for this reason that the wise considered the science of sound to be the most important science to use in every condition of life: in healing, in teaching, in evolving, in accomplishing all things in life. It is on this foundation that the science of zikr was developed by the Sufis, and that the Yogis made mantrashastra. By zikr is not meant one particular phrase: by zikr is meant a science of words.