Giving lessons after prayers is something that is permissible, and it comes under the heading of means that are permissible in principle. This is proven on the basis of the Sunnah and the practice on a large scale that has been ongoing since the best of generations. There is nothing wrong with giving a lesson before Jumu`ah so long as it does not distract the worshippers or take up too much space, especially if there is a need for that.

The opinion that permits this practice when needed is both valid and well-founded. There is no blame on those who follow this opinion. However, one should not take this matter lightly. The repetition of the Jumu`ah prayer in the same masjid (mosque) should only occur when there is a genuine need.

1- The valid excuses for missing the Jumu`ah prayer are: being sick or doing essential work that one cannot leave as in the case of one who is treating the sick or dealing with emergency cases in the hospital, or one who works as a security guard for a place of great importance, and other such jobs. 2- If your presence in the hospital at the time of Jumu`ah prayer is necessary for dealing with emergency and accident cases, then there is nothing wrong with your not attending Jumu`ah prayer.