उत्सन्नकुलधर्माणां मनुष्याणां जनार्दन।नरकेऽनियतं वासो भवतीत्यनुशुश्रुम॥
utsanna-kula-dharmāṇāṃ manuṣyāṇāṃ janārdananarake ‘niyataṃ vāso bhavatītyanuśuśruma
Word by word
The verse says
And we have heard, Krishna, that those whose household duties are destroyed dwell in hell for as long as anyone knows.
In plain words
And there it is: we have heard.
After five verses of confident doctrine, he attributes the whole thing. It is not his reasoning. It is what he was taught.
He does not seem to notice that he has just undercut himself. He has spent his strongest-sounding verses reciting.
Where you've felt this · in study
You finish making a case and then add well, that's what I've always been told. The sentence slips out. It is more honest than everything before it, and you can hear yourself hearing it.
Going deeper
Iti anuśuśruma — thus we have heard. The verb is the one used for receiving sacred teaching from a teacher.
This is the most revealing phrase in Arjuna's entire speech, and it is almost always read past. He is telling Krishna, and himself, that the last five verses were borrowed. The elaborate account of family collapse, hell and fallen ancestors is a recitation.
Which puts the whole chapter in order. Arjuna's body failed in verse 30. Everything from verse 31 to here has been the mind working backwards from that failure, borrowing heavier and heavier material, until at the end he is quoting.
And it explains Krishna's response, which otherwise looks brutal. He does not argue with the social theory, because Arjuna does not actually hold it. He goes after the state underneath — and he begins, in 2.2, by asking where this weakness has come from at such a moment. Not unkind. Just aimed at the right thing.