Less intelligent men cannot conceive of the transcendental all-spiritual form of the Lord, but they are astounded by His different energies, just as the aborigines are struck with wonder by the manifestation of lightning, a gigantic mountain or a hugely expanded banyan tree. The aborigines praise the strength of the tiger and the elephant because of their superior energy and strength. The asuras cannot recognize the existence of the Lord, although there are vivid descriptions of the Lord in the revealed scriptures, although the Lord incarnates and exhibits His uncommon strength and energy, and although He is accepted as the Supreme Personality of Godhead by learned scholars and saints like Vyāsadeva, Nārada, Asita and Devala in the past and by Arjuna in the Bhagavad-gītā, as also by the ācāryas like Śaṅkara, Rāmānuja, Madhva and Lord Śrī Caitanya in the modern age. The asuras do not accept any evidential proof from the revealed scriptures, nor do they recognize the authority of the great ācāryas. They want to see with their own eyes at once. Therefore they can see the gigantic body of the Lord as virāṭ, which will answer their challenge, and since they are accustomed to paying homage to superior material strength like that of the tiger, elephant and lightning, they can offer respect to the virāṭ-rūpa. Lord Kṛṣṇa, by the request of Arjuna, exhibited His virāṭ-rūpa for the asuras. A pure devotee of the Lord, being unaccustomed to looking into such a mundane gigantic form of the Lord, requires special vision for the purpose. The Lord, therefore, favored Arjuna with special vision for looking into His virāṭ-rūpa, which is described in the Eleventh Chapter of the Bhagavad-gītā. This virāṭ-rūpa of the Lord was especially manifested, not for the benefit of Arjuna, but for that unintelligent class of men who accept anyone and everyone as an incarnation of the Lord and so mislead the general mass of people. For them, the indication is that one should ask the cheap incarnation to exhibit his virāṭ-rūpa and thus be established as an incarnation. The virāṭ-rūpa manifestation of the Lord is simultaneously a challenge to the atheist and a favor for the asuras, who can think of the Lord as virāṭ and thus gradually cleanse the dirty things from their hearts in order to become qualified to actually see the transcendental form of the Lord in the near future. This is a favor of the all-merciful Lord to the atheists and the gross materialists.
Ref >> Srila Prabhupada Vani.