What is the ruling on giving lessons after prayers, and what is the evidence for that from the Sunnah? Is it permissible for the Imam to give a lesson before or after prayers? Can he give a lesson before the Friday sermon?

First: Delivering lessons after prayers is legislated and is one of the most opportune times for teaching Islamic knowledge. The Prophet, peace and blessings be upon him, used to preach to people after prayers, taking advantage of their gathering. It has been authentically narrated from the Companions and the great Imams that this practice was continuous.

Second: As for delivering lessons before Friday prayer, some scholars disliked it while others permitted it, based on their differing views regarding the reason for the prohibition of forming circles (halaqat) before the prayer on Friday. The majority hold that the prohibition is one of dislike (karahah) because it might interrupt the rows, or distract people from prayer or listening to the sermon. Others have gone to the extent of saying that there is no harm in it as long as it does not constrict the space for people.