Mark 9:33-35

33They arrived at Capernaum; and when He was in the house, He asked them, “What were you discussing and arguing about on the road?”

34But they kept quiet, because on the road they had discussed and debated with one another which one [of them] was the greatest.

35Sitting down [to teach], He called the twelve [disciples] and said to them, “If anyone wants to be first, he must be last of all [in importance] and a servant of all.”