It is common practice for Muslims, especially those residing in Western countries, to open the doors of their mosques and welcome non-Muslims. One such example, is the annual Big Iftar during the month of Ramadhan where people of all faith and none join Muslims to break the fast. These gatherings help to create harmony and understanding between people of different religious inclinations. Whilst most scholars believe that there is no problem in non-Muslims visiting mosques, the two holy mosques located in Saudi Arabia (Masjid al-Haram in Mecca and the Prophet’s Mosque in Medina) are still a point of contention. Currently non-Muslims are barred from entering these holy mosques and this raises the question regarding the permissibility of non-Muslims entering mosques.1
The argument put forth by Muslim scholars who believe that non-Muslims are not permitted relies on the Quranic verse:
“Oh, you who have faith, indeed the polytheists are filthy (najas). Thus, let them not enter Masjid al-Haram after this year.”2
This verse only refers to Masjid al-Haram, however some think that by extension it covers the Prophet’s mosque.3 Although this verse is limited to polytheists, Muslim scholars normally use the following verse of the Quran to demonstrate that Christians and Jews, who are commonly known as monotheists, also engage in polytheism:
“The Jews say, “Ezra is the son of Allah,” while the Christians say, “The Messiah is the son of Allah.” Such are their baseless assertions, only parroting the words of earlier disbelievers. May Allah condemn them! How can they be deluded?”4
Accordingly, it is argued that non-Muslims per se are prohibited from entering the two mosques due to their impurity. Furthermore, the Quran mentions the reprehensibility of calling other than Allah in the mosque,
“The places of worship are [only] for Allah, so do not invoke anyone besides Him.”5
However, this interpretation is unsound considering that after the revelation of the verse 9:28, Prophet Muhammad welcomed a Christian delegation from Najran into Masjid al-Nabawi and allowed them to pray in the mosque. He sent a letter to the Christians of Najran inviting them to convert to Islam who in turn sent a delegation, including their scholars, to engage in discussion with the Prophet in Medina. The Christians refused to convert to Islam and the Prophet maintained that some of their beliefs were incorrect. Nonetheless, the Prophet gave them a place to stay and let them pray facing East which reportedly made some Muslims uncomfortable.6 From this, and other traditions, we gain an insight into the function of the mosque during the time of the Prophet.7
Accordingly, the meaning of polytheists and impurity in the aforementioned verse has to be understood in light of the Prophet inviting the Christians of Najran and the general function of the mosque. It seems that the context is that of the pagans entering Mecca in pre-Islamic Arabia with their idols to carry out practices such as performing the pilgrimage naked. Therefore, considering that the Prophet allowed the delegation of Christian scholars to enter and worship inside Masjid al-Nabawi, it can be concluded that non-Muslims are permitted to enter all Muslim mosques (or places of worship). The Quran only forbids non-Muslims (or polytheists) from entering mosques if they are to practice worshipping more than one God.
 Kathy Cuddihy, An A to Z of Places and Things Saudi, (Stacey International, 2001), 148.
 Quran 9:28.
 The founding scholars of the Sunni jurisprudential schools, all interpret the remit of the verse differently. Qurtubi, Jāmiʾ lī aḥkām al-Quran; Shirāzī, al-Muhadhdhab; Nawawī, Majmūʾ; Kasani, Badaʾi al-Sanaʾi
 Quran 9:30.
 Quran 72:18.
 Muhammad Zafrulla Khan, Muhammad: Seal of the Prophets, (Routledge: 1980).
 There is a reported tradition in al-Kāfī which recounts an encounter between the sixth Shīʿī Imam, al-Jaʿfar al-Ṣādiq and ibn Abī al-ʿAwjāʾ, who was an unbeliever, in the mosque. When the Imam asked him why he was in the mosque, al-ʿAwjāʾ replied, “it is the societal custom of the people to engage in conversations in the mosque and meet.” al-Kāfī, vol. 1, pp. 77-78