Mark 10:42 But Jesus called them to him, and saith unto them, Ye know that they which are accounted to rule over the Gentiles exercise lordship over them; and their great ones exercise authority upon them.
43 But so shall it not be among you: but whosoever will be great among you, shall be your minister:
44 And whosoever of you will be the chiefest, shall be servant of all.
45 For even the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
One of the aspects of servant leadership is the matter of ministering to others. In this case ministry does not mean preaching or directing others, but rather helping them. Jesus exemplified this in His large number of healings of individuals and multitudes. Read more
Matt 20:25 But Jesus called them unto him, and said, Ye know that the princes of the Gentiles exercise dominion over them, and they that are great exercise authority upon them.
26 But it shall not be so among you: but whosoever will be great among you, let him be your minister;
27 And whosoever will be chief among you, let him be your servant:
28 Even as the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
The original disciples of Jesus did not have a good understanding of the nature of His kingdom and the leadership of it. I am not sure that nearly two thousand years down the road we have much more clarity about the matter. Read more