Bhagavad Gita
1.42

दोषैरेतैः कुलघ्नानां वर्णसङ्करकारकैः | उत्साद्यन्ते जातिधर्माः कुलधर्माश्च शाश्वताः ||४२||

doṣhair etaiḥ kula-ghnānāṁ varṇa-saṅkara-kārakaiḥ utsādyante jāti-dharmāḥ kula-dharmāśh cha śhāśhvatāḥ

Translation

By the evil deeds of those who destroy the family tradition and thus give rise to unwanted progeny, a variety of community projects and family welfare activities are ruined.

Interpretation

The cumulative social destruction from war — the collapse of family, community, dharmic tradition — is Arjuna's argument for why this war should not be fought. He is not wrong about the social consequences, but he lacks the wider perspective that Krishna will provide.