सङ्करो नरकायैव कुलघ्नानां कुलस्य च। पतन्ति पितरो ह्येषां लुप्तपिण्डोदकक्रियाः ॥

saṅkaro narakāyaiva kula-ghnānāṁ kulasya cha patanti pitaro hy eṣhāṁ lupta-piṇḍodaka-kriyāḥ

This confusion draggeth to hell the slayers of the family, and the family; for their ancestors fall, deprived of rice-balls and libations.

In plain words: Arjuna says this mixing of the social order sends both the family and those who destroyed it to hell. He adds that the ancestors suffer too, because no one is left to offer them the rice-balls and water of the traditional memorial rites.