Is it permissible to train people in karate inside the mosque?

The basic principle is to keep mosques free from idle talk and raising voices, because they were built for the remembrance of Allah and the establishment of prayer, as Allah Almighty said: "In houses which Allah has permitted to be raised and that His name be remembered therein."

Some scholars have gone to the extent of permitting playing with spears and anything that strengthens one for jihad in the mosque, based on the saying of Allah Almighty: "And prepare against them whatever you are able of power," and because the Prophet (peace be upon him) permitted the Abyssinians to play with spears in the mosque. This is extended to include anything similar that aids in jihad and acts of righteousness.

Therefore, if karate training in the mosque helps in jihad, then it is permissible, provided that the time and place are considered so as not to cause discord among people.