“Afterward Jesus went up on a mountain and called out the ones he wanted to go with him. And they came to him. Then he appointed twelve of them and called them his apostles. They were to accompany him, and he would send them out to preach, giving them authority to cast out demons.”
Mark 3:13-15 NLT. http://bible.com/116/mrk.3.13-15.nlt
Leadership is making sure to train your replacement.
A true sign of leadership is to develop leaders. It's not good enough to be organized, possess great insight or have a dynamic message. What will happen when you leave? I don't care who you are you will retire at some point. You can't live forever in your current job or ministry. If the success of your company, school, ministry, family, or church is solely dependent upon you, it can not remain successful forever.
Jesus chose twelve men to mentor. He taught them and helped them prepare to reach out on their own. I need to be deliberate in doing the same thing and I'm just not good at it. I need to walk along side new leaders, help them, but not do for them. I need to do the same with colleagues and students. I must train them up in service, love, and caring for their fellow man. I can't get caught up in being the "boss". I need to serve to lead. I need to build up others to serve for the long haul.