Karna Vows to Kill Arjuna Before Duryodhana
Duryodhana sits surrounded by his brothers after completing a great sacrifice. Karna rises and speaks of honoring him again — after the Pandavas are dead and a rajasuya is performed. Then Karna makes a public vow: he will not wash his feet until Arjuna is killed.
Duryodhana sat on an excellent seat, surrounded by his brothers. The great sacrifice was complete. The hall was full.
Karna rose and spoke to him. "O foremost among Bharatas! It is through good fortune that your great sacrifice has been completed. O best of men! When you have killed the Parthas in battle and have performed a rajasuya, I will honor you again."
Duryodhana replied, "O brave one! You have spoken the truth. O best among men! When the evil-souled Pandavas have been killed and the great sacrifice of rajasuya has been performed, you will honor me again."
He embraced Karna. And then he began to think about rajasuya — the greatest of sacrifices, the one that proclaimed a king's supremacy over all other kings. He turned to the Kouravas beside him. "O Kouravas! When will I perform the supreme and extremely expensive sacrifice of rajasuya, after having killed all the Pandavas?"
Karna answered him directly. "O elephant among kings! Listen to my words. I will not wash my feet until Arjuna is dead."
When Karna vowed to kill Phalguna — Arjuna — in battle, Dhritarashtra's sons roared in approval. They were maharathas, great archers, every one of them. Their roar filled the hall. And in that moment, Dhritarashtra's sons thought that the Pandavas had already been conquered. Aranyaka Parva, Chapter 540