‘Āisha (radiya allahu 'anha) said: ‘The Messenger of Allah (salla Allahu alayhi wa sallam) instructed us to build mosques in our places of residence, and that they be cleaned and perfumed.’ -Mundhirī said: ‘It was related by Aḥmad and Tirmidhī (who declared it rigorously authentic), and by Abū Dāwūd and ibn Mājah.' Samra ibn Jandab said: ‘The Messenger of Allah (salla Allahu alayhi wa sallam) instructed us to make mosques in our homes, and instructed us to clean them.’ -Narrated by Aḥmad and Tirmidhī, who declared it rigorously authentic. (Al-Targhīb) So the Prophet (salla Allah alayhi wa sallam) enjoined the maintenance of the cleanliness of mosques both public and private, that is those mosques that are built in houses as a place to offer supererogatory and night prayers, and to worship Allah therein, which is a desired Sunnah according to the scholars. (From Our Master Muhammad the Messenger of Allah - salla Allah alayhi wa sallam, by Imam Abdullah Sirajuddin.)