Mark 9:33-35

And they arrived at Capernaum; and when [they were] in the house, He asked them, What were you discussing and arguing about on the road? But they kept still, for on the road they had discussed and disputed with one another as to who was the greatest. And He sat down and called the Twelve [apostles], and He said to them, If anyone desires to be first, he must be last of all, and servant of all.