With the destruction of the family perish the eternal duties of the family; when duty perishes, impiety overcomes the whole family

Here begins the chain of consequences Arjuna fears. Kula-kṣaye (in the destruction of family) as absolute condition: the kula-dharmāḥ (duties of family) — ceremonies, sacrifices, care of ancestors — are sanātanaḥ (eternal, perpetual) but not indestructible.

Praṇaśyanti (perish completely) is strong. The verb implies total extinction, not mere suspension. When these duties (dharme) are lost (naṣṭe), adharmaḥ (anti-order, ethical chaos) abhibhavati (dominates, invades, conquers completely) the whole family (kṛtsnam).

The uta (also, and moreover) anticipates more consequences in the following verses.