I can think of no better illustration of this truth than one from my own religious tradition. Jesus of Nazareth, facing his own eminent death, gathered his friends together for a meal. Before they ate he took a basin and towel and washed their feet. Foot-washing as a metaphor of servanthood is a compelling one. Foot-washing requires an uncommon humility and a profound concern for the other.
Servant leaders are foot washers.
They are selfless, serving others without thought of reward. They seek to empower others, to make leaders out of others. Their concern is always the well-being of others. They are not distracted by self-importance. There is, of course, only one way.