Tag Yoga Sutra1.23

While calling for devotion to God as a Prerequisite for realizing Godhood or attain Reality, Hinduism also states that the Reality if name less Formless.

For details please read my post God Has Name s and Forms, Yes and No"

The Reality is described as Sat, being, Chit, Consciousness and Ananda, Bliss.

The Upanishads call the worship of deities as inferior.

In the Bhagavad Gita Lord Krishna states that, I appear to one in what ever Form he worships Me , I grant him his wishes in the Form He worships"

Then why the concept of God at all if it is not necessary

One does not become a Ph.d straightaway, has o go through schooling step by step.

But, once you reach Higher Level of Learning, the earlier levels seem redundant.

But it must not be forgotten that without that one would not reached the present level.

In the same way the concept of God is necessary for Spiritual development.