Hare Krsna,
This has been one of the difficult forum topics to meditate upon. The manifestations of various forms of the Lord such as virat-rupa, arca-vigraha, etc. are actually a mercy of the Lord upon the conditioned living entities. These manifestations are actually meant for the neophyte devotees who may have difficulty in immediately accepting the transcendental eternal form of the Lord.
“Lord Kṛṣṇa exhibited this virāṭ or viśva-rūpa to Arjuna just to convince the impersonalists that He is the original Personality of Godhead… The virāṭ-rūpa is not, therefore, an eternal form of the Lord exhibited in the spiritual sky; it is a material manifestation of the Lord. The arcā-vigraha, or the worshipable Deity in the temple, is a similar manifestation of the Lord for the neophytes. But in spite of their material touch, such forms of the Lord as the virāṭ and arcā are all nondifferent from His eternal form as Lord Kṛṣṇa.” (SB 3.6.4 P)
“This virat-rupa 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 virat-rupa and thus be established as an incarnation.” (SB 2.1.24 P)
We also know that Krsna displayed His universal form to Arjuna (on the battlefield) and Yasoda (when she asked Krsna to open His mouth to check if He has eaten dirt). The question to ponder is, if the virat-rupa forms are meant for the less intelligent, why would Krsna display them to Arjuna and Yosada – His pure devotees. The reason is mentioned in BG Chapter 11 (The Universal Form).
“The Lord can understand also that Arjuna wants to see the universal form to convince others. Arjuna did not have any personal desire for confirmation. Kṛṣṇa also understands that Arjuna wants to see the universal form to set a criterion, for in the future there would be so many imposters who would pose themselves as incarnations of God. The people, therefore, should be careful; one who claims to be Kṛṣṇa should be prepared to show his universal form to confirm his claim to the people.” (BG 11.3 P)
There are numerous places in the scriptures where the Lord displayed His universal form. One such instance is where Lord Vamanadeva displayed the universal form to Bali Maharaja.
“Vāmanadeva first expanded Himself to the universal form and then reduced Himself to the original Vāmana-rūpa. Thus, He acted exactly like Lord Kṛṣṇa, who, at the request of Arjuna, first showed His universal form and later resumed His original form as Kṛṣṇa. The Lord can assume any form He likes, but His original form is that of Kṛṣṇa (kṛṣṇas tu bhagavān svayam). According to the capacity of the devotee, the Lord assumes various forms so that the devotee can handle Him. This is His causeless mercy.” (SB 8.21.5 P)
In another instance, Sri Caitanya Mahaprabhu showed the universal form to His intimate devotees. Sri Caitanya-caritamrita (Adi 17.10) briefly mentions that Advaita Acharya had a vision of the virat-rupa. Sri Caitanya-bhagavata (Madhya 14) elaborates, saying that both Sri Advaita and Nityananda Prabhu were privy to this confidential manifestation of the Supreme and upon seeing it danced like jubilant peacocks. They felt that because of this form the world would now become aware of Lord Caitanya’s divinity.
My personal realization from this lesson is that it teaches us to be humble and fully dependent on Krsna. A lot of simple things that we take for granted such as opening and closing of our eyes, breathing in and out, etc. are actually made possible by the power of the Supreme Lord. He has empowered each controlling demigod to help us with the functioning of these senses. This proves that we living entities do not have power to do anything. Everything comes from the Supreme Lord. Therefore we must seek guidance from the Supreme Lord for everything just as the demigods did. We must align our plans with His plan. The Lord can reveal Himself only to a person who is submissive and who engages in His transcendental loving service. The demigods controlling the elements and ingredients of universal affairs prayed to the Lord for guidance, and thus He manifested His gigantic form, as He did at the request of Arjuna.
All glories to Srila Prabhupada!
Krsna Katha 