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 brahmana or a so-called son of a brahmana, has to be punished in all circumstances. When Arjuna promised to behead the aggressor named Asvatthama, he knew well that Asvatthama was the son of a brahmana, but because the so-called brahmana acted like a butcher, he was taken as such, and there was no question of sin in killing such a brahmana's son who proved to be a villain.