And Jesus called them to him and said to them, “You know that those who are considered rulers of the Gentiles lord it over them, and their great ones exercise authority over them. But it shall not be so among you. But whoever would be great among you must be your servant, and whoever would be first among you must be slave of all. For even the Son of Man came not to be served but to serve, and to give his life as a ransom for many.” (Mark 10:42-45)
This flies in the face of everything the world tells us. That shouldn't surprise us since our Lord's Kingdom is not of this world. The challenge to us as the church is to avoid the world's definition of greatness and instead to strive after that of Christ.
What does this look like in day-to-day living? I believe it means that we take opportunity to do for others and set examples for others. Instead of being concerned about status or authority, we simply try to help other people as they have need.
As I think back on my life, the greatest people I have known have been servants. Some of these folks have held positions of leadership in the church while others have not. Regardless, it was the service that I recall fondly. That's what made them great.