When Mahisasura satisfied Brahma with austerities, Brahma wanted to give him a boon. Mahisasura listened to Brahma and asked for immortality. The demons can't kill me. Brahma then went away saying tadastu. Hearing this, Mahishasura began to conquer all the places of heaven and hell unjustly. The Supreme **** Sri Vishnu never despises the power of Goddess. Where Mahisasura is killed by the roar of all caste and female power and use of weapons. Her pride and contempt of goddess power is destroyed. In other words, Mother Durga is instructing to remove all the oppression of the society with 8 hands of 4 letters and 2 hands of female power for a total of 10 hands.