In this book, the purpose of building mosques, the reward of building mosques, the importance of mosques in society, the virtues of mosques, the virtues of Masjid Haram, Masjid Nabawi and Masjid al-Aqsa, virtues of Masjid Quba, virtues of cleaning mosques, in mosques. Permissible matters and impermissible matters have been explained in the light of Sahih hadiths.