We are a group of young men in a foreign country, inviting Germans to Islam through a committee at our mosque, and we undertake various da‘wah activities. We face a problem regarding the entry of un-veiled and non-Muslim women into the mosque, as some object to it. We ask about the legal rulings concerning this matter, and is it true that the Prophet, may Allah’s prayers and peace be upon him, allowed non-Muslims into his mosque for da‘wah?

All praise is due to Allah, and prayers and peace be upon the Messenger of Allah, and upon his family and companions. It is permissible for a disbeliever to enter mosques, except for the Sacred Mosque (Masjid al-Haram (definition)), when there is a need to invite them to Islam. When inviting women, caution must be exercised and the following controls must be adhered to: lowering the gaze, the presence of a mahram (definition), avoiding seclusion, and leaving the door open. Adhering to the manners of Islam is the greatest means of da'wah (invitation) and influence.