Q. What is the reason for the Imam to hold the staff at the time of the Khutbah of Jumuah?
A. It is a preferred act (Mustahab) for the Imaam/Khateeb to hold a staff (Asaa) with his left hand whilst delivering the Khutbah of Jumuah.
The scholars of Jurisprudence (Fuqahaa) have written that if the Muslims conquer a city by the sword, the Imaam should hold a sword whilst delivering the Khutbah, signifying the authority of the Muslims.
However, if the Muslims do not conquer a city by the sword but through the efforts of propagating Islam or there is a truce/agreement in place, then the Imaam may hold a staff whilst delivering the Khutbah. (Shaami 2/163/Fatawaa Darul Uloom Zakariyya 2/706)
Note: The above will be preferred (Mustahab) provided that it is not considered obligatory, compulsory or an emphasized Sunnah act.
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa