Muslims do have leaders, office bearers of varying degrees to lead Islam and Muslim Ummah. How can Muslims help their leaders?

Question

Muslims should help their leaders, whom they choose, to establish justice, equality etc. Thus, giving a Bay’ah (pledge of allegiance). One of our pious predecessors defined Bay’ah as a pledge of obedience. It is as if the person who gives the pledge of obedience to his leader, promises that he will accept his rules concerning matters and the matters of all Muslims as well. He will never dispute with him and will follow his orders willingly or unwillingly. The people used to put their hands in the hand of the ruler when they gave the pledge of allegiance to confirm the pledge just as a seller and a buyer do to confirm their contract.