आख्याहि मे को भवानुग्ररूपो नमोऽस्तु ते देववर प्रसीद। विज्ञातुमिच्छामि भवन्तमाद्यं न हि प्रजानामि तव प्रवृत्तिम् ॥

ākhyāhi me ko bhavān ugra-rūpo namo ’stu te deva-vara prasīda vijñātum ichchhāmi bhavantam ādyaṁ na hi prajānāmi tava pravṛittim

Reveal Thy Self; what awful Form art Thou? I worship Thee! Have mercy, God supreme! Thine inner Being I am fain to know; This Thy forth-streaming Life bewilders me.

In plain words: Frightened, Arjuna bows and begs for mercy. He asks Krishna who he really is in this awful form, because he cannot understand what he is seeing.