The whole manifestation being the phenomenon of sound, the knowledge of sound is the key to the mystery. The knowledge of sound acts as a guide in the maze of names and forms. That is the reason for the great importance attached by the Yogis to mantra yoga which to the Sufis is zikr. There is nothing man cannot accomplish by the power of zikr, if only he knows which zikr, how to use it, and for what purpose. Just as there is creative power in sound, so is there also destructive power, as in the Scriptures the expression "the blast of the last trumpet" signifies the destructive power of the sound.