He can be with form, without form and also beyond all that.
Swami Shantatmananda writes in a column in the Sunday Guardian:
“Sri Ramakrishna would often caution his devotees about the dangers of being rigid in one’s spiritual beliefs. He would ask the devotees whether they knew where those who speak of the formless God make a mistake. He himself would answer stating that it was when they said that God was formless alone and those who differ from this view were wrong. He would say that God was both with and without form and not only that, he might have many more aspects and that it was possible for Him to be everything.
“He used to describe in a soul-elevating way his own spiritual experience in this regard. He said, “Chit Shakti Mahamaya has become the 24 cosmic principles. One day as I was meditating, my mind wandered away to Rashik’s house. You know that he does the job of cleaning. Initially, my mind was refusing to stay at his place. Then I scolded my mind and commanded it to stay at that very place. Then the Divine Mother revealed to me that the men and women in that house were mere masks and inside them were the same hidden divine power that rises up through the six centres of the body.“
“Through the above spiritual experience Sri Ramakrishna conveyed the idea that the estimation of high and low, which men make about others, is irrelevant and wrong. These were mere outer shells and the kernel inside each was the same divinity. Thus it is difficult to fathom or estimate the nature of God. He can be with form, without form and also beyond all that. A true spiritual aspirant will pursue the path most congenial to himself or herself. Such a person would be deeply interested in achieving the goal and would not be bothered by meaningless discussions and hair-splitting arguments. They are broad-minded enough to accept that every idea about God needs to be accepted and respected.”
Sri Ramakrishna said one day to Manilal, a member of the Brahmo Samaj, who believed in a formless God: Kabir used to say: ‘God with form is my Mother, the formless God my Father. Whom should I blame? Whom should I adore? The two sides of the scales are even.‘
When Lord Krishna says, वासुदेवः सवॅमिति । ( Bhagavad Gita 7/19) All this is vasudev, means God, he points out that God is in formless state as well as in formful mode. In fact, all the forms are of this formless. so one can according to his faith and taste worship any of the two, formless or formful.
Sri Ramakrishna said to one visitor from Nanak sect who believed only in a formless God:
“Dive deep; one does not get the precious gems by merely floating on the surface. God is without form, no doubt; but He also has form. By meditating on God with form one speedily acquires devotion; then one can meditate on the formless God. It is like throwing a letter away, after learning its contents, and then setting out to follow its instructions.”
The Brihadaranyaka Upanishad (2.2.1) says that Brahman has two aspects, Formful (Murta) and Formless (Amurta).
Swami Tapasyananda explains in his English translation of Vishnu Puri’s Bhakti Ratnavali – An Anthology from Bhagavad Gita thus:
“The Puranas including the Bhagavata accept both these aspects, but concentrate particularly on the Formful Aspect, which is the more significant for the devotional mind. What is called the Formless is the Non-dual Absolute and the Formful is the Sakti or the manifesting Power of the Formless, without which the Formless will be indistinguishable from a Nikhil (Sunya). In the same way if the Formful alone is accepted without the Formless or the Infinite and Absolute Being as its complement, the former will be only a limited entity indistinguishable from an exalted man.
“So the Puranas in general, and the Bhagavata in particular accept the Supreme Being as Murta and Amurta, with a greater stress on the Murta aspect and call Him the Bhagavan. …
“So the Puranas try to depict, and impress on man, the Divine majesty of the Bhagavan through symbolic and, at the same time, highly realistic description of this Archetypal Form — His divine attributes, His abode, paraphernalia, decorations, weapons, attendants, creative and redemptive activities, incarnations, associations with sages and devotees — in fact with such a variety of details and highly poetic touches, and with such a realism as we cannot imagine with regard to any noted individual in our earthly plane of existence.
“In these highly artistic descriptions, care is taken at every step to impress on man the supra-human and transcendent nature of the object dealt with, and that accounts for many of their unearthly and unusual features.
“When the details of these descriptions are taken in isolation and scrutinised, they look queer and bizarre; but the cumulative and synergistic effect they produce, when taken as a whole, with a receptivity born of Sraddha, is to make a tremendous impact of Divine consciousness on the mind.
“No literature in the world has succeeded in making God a reality to man by such vivid and realistic descriptions as the Puranas have done.”
(Collection of quotes/extracts in this post by Yogasimhaputra with no originality claimed. – Courtesy to the learned Gurus)