They needed this example. In fact, in Luke’s Gospel, and in Matthew and Mark, we read that just before this happens and they went into the upper room, they had been arguing about who would be the greatest among them. So perhaps they were all a bit heady when they went into that room, dreaming of greatness in the court of the conqueror Messiah. And Christ brings them down to earth. I will now do what none of you have done, you were too high and mighty. I will do it. And he demonstrates his humiliation at the same time.