The disciples are falling out over the behaviour of two of their number. Jealousy and rivalry can spring up so quickly in any group. It stems, in this case, from their desire to have power like those who rule Jerusalem. Jesus intervenes to call them to his own example of a willingness to be a slave. He will treat his life as something to be given up for the good of others.
Photo by Quicksandala on Morguefile
And here is a short talk based on the same passage: He Changed The World (Episode 43)
Ransom