Luke 22:7-30
But not so with you. Rather, let the greatest among you become as the youngest, and the leader as one who serves. (Luke 22:26 ESV)
One of the biggest flaws I fall into sometimes is thinking I am more awesome than I actually am. I just have a natural tendency to think quite a lot of myself. The problem with that kind of thinking is that it is rooted in pride. And it pushes me toward selfishness rather than selflessness.
In the Upper Room Jesus stressed the importance of selflessness to his disciples. He knew that once he was no longer there to physically walk them through every step those guys were going to need to be selfless. The spread of Christianity would count on their willingness to put the message, and the hope it brings, ahead of their own selfish tendencies.
The youngest among Jesus' disciples was a guy named John. Some theologians believe John was only about 17-20 when he travelled with The Lord. And the Jewish culture of that era was not always one that esteemed the opinions of younger generations. Still, Jesus thought it pertinent to compare leading and serving to becoming like a young man.
The authority of leadership is not inherent in a position, it is a gift from the Father. Position is not had to garner esteem, but it is brandished to enable selfless acts of servanthood. For a wise old leader to be effective, he would have to humble himself, and realizing the source for all he has and does, he must become as the youngest.