Sanctity of Mosques and Avoidance of False Stories
Excerpt taken from the book Aḥkām al-Masājid by Shaykh Muhammad Munir Qamar
The Problem of Storytellers in Mosques
Some people, instead of being true khateebs and preachers, indulge in fabricated and false narrations on the pulpits of mosques. They assume that only such stories bring “color” to their sermons. Without distinguishing between authentic and fabricated, they mix false tales into their eloquent speeches.
Such people deserve to be called “mosque storytellers” rather than preachers. Imām al-Ghazālī, in Iḥyā’ ʿUlūm al-Dīn, used this exact term and mentioned in his discussion on wrong practices in mosques (munkarāt al-masājid):
Storytellers and preachers who speak innovations are among the wrongs of mosques.
If a storyteller narrates false incidents, he is a fāsiq (sinner) and must be stopped.
Likewise, if a preacher is an innovator, he too must be restrained.

Clarification
Thus, not only vain poetry but also storytelling and preaching based on weak, fabricated, and false reports are forbidden in mosques.
If such mistakes happen out of ignorance, that is another matter. However, anyone who speaks in a mosque should:
✔ Prepare properly.
✔ Verify what they intend to say.
✔ Ensure it is based on authentic knowledge.
So that they may avoid the severe warnings regarding lying against the Prophet ﷺ.
Duty of Mosque Custodians
Mosques must be kept pure and free from such practices. If caretakers of mosques lack the knowledge to handle this, they must at least seek the help of scholars to protect their mosques from these wrongs.
❀ The sanctity and respect of mosques demand that they be safeguarded from fabricated stories, weak narrations, and baseless preaching.