BG 1.43

O Kṛṣṇa, maintainer of the people, I have heard by disciplic succession that those whose family traditions are destroyed dwell always in hell.

1.43. On account of these evils of the family-ruiners that cause the intermixture of castes, the eternal caste-duties and family-duties fall into disuse.

1.43 By the destruction of our lineage and the pollution of blood, ancient class traditions and family purity alike perish.

1.35 1.44 Nihatya etc. upto anususruma. Sin alone is the agent in the act of slaying these desperadoes. Therefore here the idea is this : These ememies of ours have been slain, i.e., have been take possession of, by sin. Sin would come to us also after slaying them. Sin in this context is the disregard, on account of greed etc., to the injurious conseences like the ruination of the family and the like. That is why Arjuna makes a specific mention of the [ruin of the] family etc., and of its duties in the passage 'How by slaying my own kinsmen etc'. The act of slaying, undertaken with an individualizing idea about its result, and with a particularizing idea about the person to be slain, is a great sin. To say this very thing precisely and to indicate the intensity of his own agony, Arjuna says only to himself [see next sloka]:

1.26 - 1.47 Arjuna said - Sanjaya said Sanjaya continued: The high-minded Arjuna, extremely kind, deeply friendly, and supremely righteous, having brothers like himself, though repeatedly deceived by the treacherous attempts of your people like burning in the lac-house etc., and therefore fit to be killed by him with the help of the Supreme Person, nevertheless said, 'I will not fight.' He felt weak, overcome as he was by his love and extreme compassion for his relatives. He was also filled with fear, not knowing what was righteous and what unrighteous. His mind was tortured by grief, because of the thought of future separation from his relations. So he threw away his bow and arrow and sat on the chariot as if to fast to death.

1.43 Sri Sankaracharya did not comment on this sloka. The commentary starts from 2.10.

1.43 By the sins of the clan-destroyers who bring about inter-mixture of classes, the ancient traditions of the clan and class are destroyed.

1.43 Due to these misdeeds of the ruiners of the family, which cause intermingling of castes, the traditional rites and duties of the castes and families become destroyed.