Question: Why did Dronacarya take revenge to acquire a kingdom from Drupada even though he was a brahmana?
Answer by Romapada Swami: Dronacarya was trained in martial skills along with Drupada. Shortly after Drupada became king, Dronacarya approached him in a friendly spirit but was treated unkindly. Dronacarya was pained to see this attitude of his friend soon after ascending the throne; he also wanted to reinstate his friendship with Drupada, but the only apparent way he could do so was to gain equal footing with Drupada. So he took away Drupada’s kingdom through Arjuna’s help, and gave back Drupada half of the kingdom so that now, as the masters of equal kingdoms, he could solicit Drupada’s friendship again. Dronacarya was not personally aspiring lordship over a kingdom; Drona’s main motivation was that Drupada had promised him his lifelong friendship and to uphold his promise and teach his friend a lesson, he acted the way he did.