As people continued to gradually embrace Islam, the number of Muslims increased until they now formed a small group. At that time, the house of Hazrat Arqam (radhiyallahu ‘anhu) was chosen as a place for all the Muslims to congregate.

Hazrat Arqam (radhiyallahu ‘anhu) was among the first Muslims, being either the seventh or tenth person to embrace Islam. His house was on Mt Safaa.

Right until Hazrat ‘Umar (radhiyallahu ‘anhu) accepted Islam, Rasulullah (sallallahu ‘alaihi wasallam) and the Sahaabah (radhiyallahu ‘anhum) would gather at the house of Hazrat Arqam (radhiyallahu ‘anhu). After Hazrat ‘Umar (radhiyallahu ‘anhu) embraced Islam, the Muslims would gather wherever they wished.

(Extracted from Seeratul Mustafa 1/171)