Jesus replied, "What do you wish me to do for you?"
How often Jesus asks each of us the same question!
They ask to sit on his right and left when he is glorified. Then Jesus tells them, "You do not know what you are asking. Can you drink the cup that I drink or be baptized with the baptism with which I am baptized?" They answer that they can.
When the other Apostles heard this, they became indignant at James and John. Then Jesus speaks to them and tells them that "whoever wishes to be great among you will be your servant; whoever wishes to be first among you will be the slave of all. For the Son of Man did not come to be served but to serve and to give his life as a ransom for many."