After witnessing the warriors being crushed in the teeth of the Universal Form, Arjuna reaches his breaking point. He cannot see the "Destroyer" any longer and pleads for the speaker to return to his peaceful, regal appearance.
The Verse:
"I am delighted to have seen what has never been seen before, yet my mind is distracted by fear. Therefore, O God, show me that same form of yours again... I wish to see You in Your four-armed form, wearing a crown and holding a mace and a disc in Your hands."
Before changing back, Kaal makes it clear that the terrifying "Soul-Eating" form is actually his real power in this realm:
"By My grace, O Arjuna, this supreme, radiant, universal, infinite, and primal form of mine has been shown to you... Neither by the study of Vedas, nor by sacrifices, nor by charities, nor by rituals, can this form be seen by anyone else in the world of men."
The Tattvadarshi Insight: Kaal is telling Arjuna that the "Peaceful Vishnu" form is what everyone sees through rituals and Vedas, but the Vishwaroop (Kaal) is the hidden reality. Both, however, are restricted to the 21 universes. Neither of these forms belongs to the Supreme God Kabir, who resides beyond the reach of Kaal’s radiance.
The Verse:
"Having spoken thus to Arjuna, the son of Vasudeva (Kaal acting through Krishna) showed him His own four-armed form again; and then the High-Souled One, assuming a gentle human form, consoled the terrified Arjuna."
Your site's "Full Detail" allows us to map the hierarchy Kaal uses to manage his "prison":
If a seeker only reaches the "Four-Armed" form of Vishnu, they have only reached the Sattva Guna of Kaal.
Arjuna wasn't scared of the 4-Armed form; he was scared of the Vishwaroop and was begging for the 4-Armed form to return because it represents peace and order.
No. The Giver of the Gita calls the Vishwaroop his "Supreme" form (Param Rupam) within this realm. However, even this is lower than the Param Akshar Brahm, who does not have a terrifying, soul-consuming nature.
To prove his hierarchy. He showed that he is the power behind the famous deities. By showing the 4-Armed form, he confirmed he is the one who functions as Brahma, Vishnu, and Shiva.