tadā śucas te pramṛjāmi bhadre
yad brahma-bandhoḥ śira ātatāyinaḥ
gāṇḍīva-muktair viśikhair upāhare
tvākramya yat snāsyasi dagdha-putrā
tadā - at that time only; śucaḥ - tears in grief; te - your; pramṛjāmi - shall wipe away; bhadre - O gentle lady; yat - when; brahma-bandhoḥ - of a degraded brāhmaṇa; śiraḥ - head; ātatāyinaḥ - of the aggressor; gāṇḍīva-muktaiḥ - shot by the bow named Gāṇḍīva; viśikhaiḥ - by the arrows; upāhare - shall present to you; tvā - yourself; ākramya - riding on it; yat - which; snāsyasi - take your bath; dagdha-putrā - after burning the sons.
An enemy who sets fire to the house, administers poison, attacks all of a sudden with deadly weapons, plunders wealth or usurps agricultural fields, or entices one’s wife is called an aggressor. Such an aggressor, though he be a brāhmaṇa or a so-called son of a brāhmaṇa, has to be punished in all circumstances. When Arjuna promised to behead the aggressor named Aśvatthāmā, he knew well that Aśvatthāmā was the son of a brāhmaṇa, but because the so-called brāhmaṇa acted like a butcher, he was taken as such, and there was no question of sin in killing such a brāhmaṇa’s son who proved to be a villain.