Link to purport by A C Bhaktivedanta Swami Srila Prabhupada

Transcript of Bhakti-Shastri class on this verse by Chaitanya Charan

Bg 1.39 

kula-kṣaye praṇaśyanti

kula-dharmāḥ sanātanāḥ

dharme naṣṭe kulaṁ kṛtsnam

adharmo ’bhibhavaty uta

Word for word: 

kula–kṣaye — in destroying the family; praṇaśyanti — become vanquished; kula–dharmāḥ — the family traditions;sanātanāḥ — eternal; dharme — religion; naṣṭe — being destroyed; kulam — family; kṛtsnam — whole;adharmaḥ — irreligion; abhibhavati — transforms; uta — it is said.

Translation: 

With the destruction of the dynasty, the eternal family tradition is vanquished, and thus the rest of the family becomes involved in irreligion.

kula-kṣaye praṇaśyanti, so when the dynasty is destroyed then kula-dharmāḥ sanātanāḥ, then kula-dharmāḥ will be destroyed. kula-dharmāḥ – every dynasty has its duty kula-dharmāḥ and that will also be destroyed, here there is some sort of contrast he is using praṇaśyanti which means destruction and sanātanāḥ which is eternal, so how something which is sanātanāḥ, eternal is destroyed? So actually that which is eternal can’t be destroyed and vice versa so here Arjuna is overpowered by illusion and he is thinking that Kula Dharma is sanātanāḥ darma

Only Bhakti Dharma is sanathana, Kula Dharma is important but it is not sanatana, in vedic culture there are two levels of dharma, Para & Apara Dharma. Family duty etc., are apara Dharma i.e. subordinate religion or lower religion, para dharma is supreme religion. So apara dharma is also important for the spouses to be faithful to each other, for the parents to take care of children, children to care for elderly parents, for relatives to care for each-other, this is also dharma, this is Kula Dharma, one has to do this, because it is not only our family duty but is also part of our apara level of dharma duty. So Kula dharma Sanatana, it is not sanatana in the sense that it is not eternal nature of the soul, but some kind of obligation has to be there in life, some kind of dutifulness has to be there in society for society to go on. So when people are destroyed what will happen, dharme naṣṭe kulaṁ kṛtsnam, so that dharma according to scripture which was there at the time of Pandavas is destroyed, adharmo ’bhibhavaty uta, then adharma will rise. 

Actually in the world Dharma and Adharma are always in conflict, and Dharma is always under attack from Adharma and if Dharma is weak immediately Adharma will take over, this happens in our heart, in society and all over the world, all over the universe and in all the universes. So adharmo ’bhibhavaty uta, Adarma will become predominant.

End of transcription.