Bhagavad Gita 1.42

सङ्करो नरकायैव कुलघ्नानां कुलस्य च।पतन्ति पितरो ह्येषां लुप्तपिण्डोदकक्रियाः ॥१.४२॥

saṅkaro narakāyaiva kulaghnānāṃ kulasya capatanti pitaro hyeṣāṃ luptapiṇḍodakakriyāḥ

Confusion of castes leads to hell for the slayers of the family, for their forebears fall, deprived of the offerings of rice-balls and libations of water.

गीता