Chapter eleven is the only place in the Gita where something happens. Everywhere else two men talk. Here Arjuna asks to see the form that has just been described to him, and Krishna answers that he cannot see it with his own eyes, and gives him a divine eye with which to look.
That detail is doing theological work. The vision is not a matter of paying closer attention or of being unusually perceptive. Ordinary human sight is described as structurally incapable of the object, and the capacity is conferred rather than acquired. Everything Arjuna then reports is reported by a faculty he did not have a moment earlier and does not keep.
What he sees is described in accumulating disorder: countless mouths and eyes, countless marvellous appearances, unnumbered divine ornaments and weapons, wearing garlands and garments, facing everywhere, with no beginning, middle or end. If the light of a thousand suns rose at once in the sky, Sanjaya says, it might resemble the splendour of that great self. Arjuna sees the whole world with its manifold divisions gathered in one place in the body of the god of gods.
His reaction is not devotion but terror. His hair stands on end. He addresses Krishna with formal titles, asks who this is in fierce form, and says he cannot find his bearings and gets no peace. The chapter is careful to make the vision unbearable rather than beautiful, which is why the tradition treats it as revelation rather than as a religious experience of the consoling kind. It ends with Arjuna asking, repeatedly, for it to stop.