Brahman, a term used in Hinduism for God Almighty, creator of entire cosmos was always impersonal, a source of magnanimous primordial cosmic energy beyond human comprehension.
Hinduism scriptures say for a spiritual traveler, one indulging in spirituality Brahman (God) is always Nirakaar (without a form) and also Nirguna (without an attribute).
This is also proved from Advaita Vedanta doctrine forwarded by Adi Shankaracharya. As per philosophy of Advaita Vedanta Brahman was the only truth of life. Nothing other than Brahman existed in cosmos. Adi Shankaracharya puts forward his doctrine of Maya (veil of illusion) to explain this.
As per doctrine of Maya (veil of illusion) the whole visible world exists only in thoughts of God Almighty. If we presume the present cosmos has a boundary then what beyond! If we assume God exists then who created God! As the present cosmos does not seem to have a boundary it could exist only in thoughts of God Almighty.
Broken down to basic building block of cosmos everything in cosmos including human form is clusters of atoms and molecules, nothing more. Only when perceived from senses point of view things appeared solid, in reality all was gaseous formation. This confirms the saying, the logic that other than Brahman God Almighty nothing existed in cosmos.
Hinduism scriptures further say that travelers of religious path, those indulging in rituals believed in Sakaar form of God (having a form) and also Saguna (one with attributes). It is difficult for entire mankind, commoners, masses to visualize, conceptualize the entity of Brahman in its entirety. Prime reason why three main attributes of God Almighty Lord Brahma, Lord Vishnu and Lord Shiva were created in Hinduism!
Nothing by the name of Brahma, Vishnu or Mahesh (Shiva) ever existed in cosmos.
Bhagavad Gita, the most sacred text of Hinduism on mother earth says entire mankind must only worship Brahman, offer all prayers to Brahman and never its attributes as all worship, prayers to attributes, various gods and goddesses finally redirects to Brahman God Almighty only.
If we believed in spirituality we also believed in Nirakaar, Nirguna form of God.
If we indulge in religious practices, rituals we believed in Sakaar, Saguna form of God.
As our belief accordingly the manifestation of Brahman, God!