ISHVARA

Brahman is described as the impersonal absolute Existence or Godhead, the all-pervading transcendental Reality; God without attributes, God beyond all description.  

 Ishvara is the name given to Brahman with attributes; the Personal God.  The three aspects of Ishvara which have been personified are Brahma the Creator, Vishnu the Preserver, and Shiva the Destroyer.  In the words of Vivekananda, Ishvara is “the highest possible reading of the Absolute by the human mind.”

Vivekananda’s comment is telling.  For a religion to go from a religion of the few, of the priests and intellectuals, to a religion of the masses, it must translate such abstractions  as “absolute Existence or Godhead,” “all-pervading transcendental Reality,” “God without attributes,” to something more readily grasped by the person on the street. 
 
Hence Ishvara, who is a kind of being, who creates, maintains, and dissolves the world, and does so in the guises of Brahma, Vishnu, and Shiva.” For the average person, it is easier to cultivate devotion to Brahma, Vishnu, and Shiva than to an abstract principle.