Drona recounted the poignant story behind his need for money.
"I learned the art of warfare at Sage Agnivesha's ashram. There, I hadn't introduced myself as Sage Bharadwaja's son. Drupada, the son of the King of Panchala, was a pupil at the same ashram. We were great friends, and Drupada promised to give me half his kingdom when he became king.
"After my education was completed, I married Kripi. When my son, Ashwatthama, was born, I was ecstatic. I did not desire wealth or fame. In my little world, I was happy and satisfied. One day, I found my son crying for milk. Unlike other children, he had never tasted milk, as I was too poor to afford it. One day, I saw him drinking rice slurry, thinking it was milk, while his friends ridiculed him. Moved by that sight, I decided to earn money.
"I then remembered my old friend Drupada, who had by then become the King of Panchala. With Kripi and Ashwatthama, I set out to visit him. Having left the two of them outside, I went to meet Drupada. I reminded him of our friendship and his promise to me. But he pretended not to recognize me, saying, 'Friendship can only be between equals. An impoverished Brahmin and a king can never be friends. I don't recall promising anyone half my kingdom. Nevertheless, since you have come, I will provide room and board for tonight.'
"Deeply insulted, I immediately left Panchala and came to Hastinapura. I wish to earn money by teaching the princes here."
"It is our good fortune to have obtained a guru like you. You will have no shortage of wealth in Hastinapura," Bhishma reassured Drona, who was well reputed as Sage Bharadwaja's son and Parashurama's student. Bhishma was familiar with Drona's great skill and knowledge.
The next day, all the princes assembled and bowed to their new guru. Drona asked, "When your education is complete, I will demand guru dakshina from you. Who among you is ready to give me the guru dakshina I desire?"
Only one answered, "I am ready." That was Arjuna, who from then on became Drona's favorite pupil.