Bhagavad Gita · 1.42

दोषैरेतैः कुलघ्नानां वर्णसङ्करकारकैः।उत्साद्यन्ते जातिधर्माः कुलधर्माश्च शाश्वताः॥

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

By the misdeeds of those who destroy families, creating social disorder, the eternal community and family traditions are ruined.

— Bhagavad Gita 1.42

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)