आख्याहि मे को भवानुग्ररूपो नमोऽस्तु ते देववर प्रसीद।विज्ञातुमिच्छामि भवन्तमाद्यं न हि प्रजानामि तव प्रवृत्तिम्॥
ākhyāhi me ko bhavān ugra-rūponamo ’stu te deva-vara prasīdavijñātum icchāmi bhavantam ādyaṃna hi prajānāmi tava pravṛttim
Word by word
The verse says
Tell me who you are, in this fierce form. I bow to you, best of gods — have mercy. I want to understand you, the first one, because I do not grasp what you are doing.
In plain words
After sixteen verses of description, a question.
Ko bhavān — who are you. He asks it of the man he has known for years.
And then the honest second half: na hi prajānāmi tava pravṛttim — I do not understand what you are up to.
Where you've felt this · in relationships
Your friend of ten years tells you something about her life you had no idea about. You do not argue and you are not angry. You just say: wait — who are you? You mean it as a real question, about somebody whose kitchen you have sat in a hundred times.
Going deeper
Asking who somebody is after years of knowing them is the most honest thing in this chapter.
Arjuna is not asking for a name. He has one, and he has been using it familiarly for years. He is asking because the person in front of him has turned out to contain something his picture could not hold, and he has noticed that his picture is now useless rather than merely incomplete.
The second half of the question is the more practical one: what are you doing. He can see the activity and cannot read the intention, which is the specific thing that has been frightening him since verse 19.
The answer he gets is one of the most famous sentences ever written, and it answers the second question rather than the first. Krishna does not say who he is. He says what he is doing, and it turns out that was the question that mattered.