The Nirguna Brahmam is without forms or attributes and is Impersonal. It is hard to visualize and comprehend for ordinary people due to their ignorance and limitations. Therefore, to make this Universal Spirit easily understandable, we have Saguna Brahmam, God with many forms and attributes who is known as the One Great God or Ishwara. Thus the average man or woman is able to offer their prayers to the Divine in any one of the several forms He has manifested to protect the universe and the humanity from great calamity, whenever the rule of righteousness declines and injustice triumphs. Every Hindu knows that, when they pray to any one of the several forms, God will accepts their prayers in that form and He will manifest again and again to protect the pious ones and destroy the evils and evil doers and establish the "Dharma."

Ithihasas, (meaning "It happened thus") are historical narrations of ancient times explaining such incarnations of Maha Vishnu as Sri Rama in Ramayana and Sri Krishna in Mahabharatha. We also have various manifestations of Siva, Vishnu, Sakthi and several others explained in the Puranas. Agamas explain the rules of building temples for God in various manifestations and the rules of rituals to be performed for these Deities. Jnana and Karma path deal with the Formless Brahmam. Bhakthi pathway supports the love, devotion and ultimate surrender to God in one of His many forms. Historically, the evolution of the system of Bhakthi and prayers to various Deities is very ancient and is as old as the Vedas. It was popular in the various primitive communities, as prayer to Siva, Vishnu, Kali and Muruga even before the teachings of Vedas spread all over the ancient land.