Knowledge of the Supreme Absolute Truth does not necessitate negation of the material manifestation but understanding of spiritual existence as it is. To think that because material existence is realized in forms therefore spiritual existence must be formless is only a negative material conception of spirit. The real spiritual conception is that spiritual form is not material form. Brahmā appreciated the eternal form of the Lord in that way, and the Personality of Godhead approved of Brahmā’s spiritual conception. In Bhagavad-gītā Lord Kṛṣṇa condemned the material conception of His body, a conception that arises because He is apparently present like a man. The Lord may appear in any of His many, many spiritual forms, but He is not materially composed, nor has He any difference between body and self. That is the way of conceiving the spiritual form of the Lord.
Reference:-SB 3.9.36