“A dispute also arose among them as to which of them was considered to be greatest. Jesus said to them, ‘The kings of the Gentiles lord it over them; and those who exercise authority over them call themselves Benefactors. But you are not to be like that. Instead, the greatest among you should be like the youngest, and the one who rules like the one who serves.'” (Luke 22:24-26, NIV)
The disciples were acting out of their corrupted nature (which, as people, we all share). This nature aspires to be the greatest of all. This nature desires to be the first of all. This nature expects to be served by all.
The correct attitude, according to Jesus, is to be as He was: The least of all. The last of all. The servant of all.
Because of what Jesus has done for all of us through His death on the cross, and through His resurrection from the dead; His summons to servitude is validated for all time and for all people. Our corrupted, natural ambitions assure nothing but strife, but our obedience to Jesus assures us life in all of its fullness. – Luther