Sunan Ibn Majah, Chapter: The Chapters on the Mosques and the Congregations

that the Prophet (saw) said: "Keep your infants, your insane and your evil ones away from your masjid (mosque)s. Avoid engaging in transaction and disputes, raising your voices, carrying out your prescribed punishments and unsheathing your swords therein. Make places for purification at their gates, and perfume them with incense on Fridays." (Maudu)