Is it permitted to allow Christians to pray in the Masjid?

No, it is not permitted for a Masjid to give Christians the stage and allow them to read their prayers whilst the Muslim congregation observes. Rather this is strictly prohibited. Since it promotes Kufr. The Masjid is for the worship of Allah Most High alone.

وَأَنَّ الْمَسَاجِدَ لِلَّهِ فَلَا تَدْعُوا مَعَ اللَّهِ أَحَدًا

And indeed, the Masaajid (Masjids) are for Allah. So do not call upon anyone beside Allah. (Surah al-Jinn, 18).

Muslims are strictly prohibited from promoting Kufr in any manner. This prohibition only intensifies when it relates to places of greater sanctity like the Masaajid. Therefore, it is completely prohibited for Muslims to allow Christians to propagate their religion in a Masjid. Christians are welcome to attend Masaajid and observe our worship or even join us. However, we do not permit Shirk or Kufr to be practiced in our Masaajid.

وَلَا يُمَكَّنُونَ مِنْ إظْهَارِ صَلِيبِهِمْ فِي عِيدِهِمْ؛ لِأَنَّهُ إظْهَارُ شَعَائِرِ الْكُفْرِ، فَلَا يُمَكَّنُونَ مِنْ ذَلِكَ فِي أَمْصَارِ الْمُسْلِمِينَ، وَلَوْ فَعَلُوا ذَلِكَ فِي كَنَائِسِهِمْ لَا يُتَعَرَّضُ لَهُمْ وَكَذَا لَوْ ضَرَبُوا النَّاقُوسَ فِي جَوْفِ كَنَائِسِهِمْ الْقَدِيمَةِ لَمْ يُتَعَرَّضْ لِذَلِكَ؛ لِأَنَّ إظْهَارَ الشَّعَائِرِ لَمْ يَتَحَقَّقْ، فَإِنْ ضَرَبُوا بِهِ خَارِجًا مِنْهَا لَمْ يُمَكَّنُوا مِنْهُ لِمَا فِيهِ مِنْ إظْهَارِ الشَّعَائِرِ. (بدائع الصنائع في ترتيب الشرائع)

They are not to be permitted to display their crosses on their day of Eid. Since it is a manifestation of the symbols of Kufr. Therefore, they are not to be allowed to display them in Muslim cities.

However, if they do so in their churches then they cannot be obstructed. Likewise, if they ring their bells in their long-established churches, they are not to be obstructed. As a display of the symbols of Kufr has not taken place.

If they ring them (the bells) outside of them (their churches) then they are not to be permitted since it does result in displaying the symbols of Kufr. (Badai al-Sanai, Imam al-Kaasaani).

وَإِنَّمَا يُكْرَهُ ذَلِكَ فِي أَمْصَارِ الْمُسْلِمِينَ، وَهِيَ الَّتِي يُقَامُ فِيهَا الْجُمَعُ وَالْأَعْيَادُ وَالْحُدُودُ؛ لِأَنَّ الْمَنْعَ مِنْ إظْهَارِ هَذِهِ الْأَشْيَاءِ؛ لِكَوْنِهِ إظْهَارَ شَعَائِرِ الْكُفْرِ فِي مَكَانِ إظْهَارِ شَعَائِرِ الْإِسْلَامِ. (بدائع الصنائع في ترتيب الشرائع)

That is disapproved in the cities of the Muslims, and they are those that have Eid and legal rulings established. Since, preventing such things is due to opposing the promotion of the symbols of Kufr, in a place where the symbols of Islam are to be made manifest. (Badai al-Sanai, Imam al-Kaasaani).

As we see in the Nusoos above, Christians are not to display symbols of Kufr in Muslim towns or cities. Therefore, they certainly will not be permitted to do so in the Masajid themselves. The point has been emphasized in numerous classical works of the Hanafi Madhab.

إنَّهُمْ إذَا حَضَرَ لَهُمْ عِيدٌ يُخْرِجُونَ فِيهِ صُلْبَانَهُمْ وَغَيْرَ ذَلِكَ فَلْيَصْنَعُوا فِي كَنَائِسِهِمْ الْقَدِيمَةِ مِنْ ذَلِكَ مَا أَحَبُّوا، فَأَمَّا أَنْ يُخْرِجُوا ذَلِكَ مِنْ الْكَنَائِسِ حَتَّى يَظْهَرَ فِي الْمِصْرِ فَلَيْسَ لَهُمْ ذَلِكَ. (فتح القدير)

When their Eid arrives, they like to parade their crosses and other things, let them do so within their historic churches as much as they please. As for doing so outside of the churches, such that they parade in the city, they are not permitted to do so. (Imam Ibn Humaam, Fath al-Qadeer).

وَإِنْ حَضَرَ لَهُمْ عِيدٌ لَا يُخْرِجُونَ فِيهِ صُلْبَانَهُمْ، وَلْيَصْنَعُوا ذَلِكَ فِي كَنَائِسِهِمْ وَلَا يُخْرِجُوهُ مِنَ الْكَنَائِسِ حَتَّى يَظْهَرَ فِي الْمِصْرِ لِأَنَّهُ مَعْصِيَةٌ وَفِي إِظْهَارِهِ إِعْزَازٌ لِلْكُفْرِ، وَأَمَّا الْكَنَائِسُ فَلَا يُمْنَعُونَ مِنْهُ كَمَا لَا يُمْنَعُونَ مِنْ إِظْهَارِ الْكُفْرِ فِيهَا. (الاختيار لتعليل المختار)

When their Eid arrives, they are not to parade their crosses. Let them do so within their churches. They are not to parade them outside of the churches, such that they do so in the city. Since it is a sin and leads to supporting Kufr. As for the churches, they are not prevented, since they are not prevented from promoting Kufr within them. (Imam al-Mowsili, al-Ikhtiyaar).

وَلَا أَنْ يُخْرِجُوا الصَّلِيبَ، أَوْ غَيْرَ ذَلِكَ مِنْ كَنَائِسِهِمْ، وَلَوْ رَفَعُوا أَصْوَاتَهُمْ بِقِرَاءَةِ الزَّبُورِ وَالْإِنْجِيلِ إنْ كَانَ فِيهِ إظْهَارُ الشِّرْكِ مُنِعُوا عَنْ ذَلِكَ، وَإِنْ لَمْ يَقَعْ بِذَلِكَ إظْهَارُ الشِّرْكِ لَا يُمْنَعُونَ، وَيُمْنَعُونَ عَنْ قِرَاءَةِ ذَلِكَ فِي أَسْوَاقِ الْمُسْلِمِينَ. (الفتاوى الهندية)

They are not to parade with the cross, or other such things from their churches. If they raise their voices with the reading of the Psalms or Gospel, then if it promotes Shirk (polytheism) then they are to be prevented. However, if it does not promote Shirk then they are not prevented. As for doing so within their churches, they are not prevented, since they are not prevented from promoting Kufr within them. (al-Fataawa al-Hindiyah).

ويمنعون عن قراءة ذلك في أسواق المسلمين كما يمنعون عن إخراج الصليب وضرب الناقوس لأن الناقوس لهم كالأذان لنا فيقع بذلك إظهار الشرك. (فتاوى قاضيخان)

They are prevented from reciting (their book) in the market places of the Muslims, like they are prevented from displaying the cross and striking the bell. Since the bell for them is like the Adhaan for us. Therefore, it leads to the promotion of Shirk (polytheism).

وَكَذَلِكَ ضَرْبَ النَّاقُوسِ لَمْ يُمْنَعُوا مِنْهُ إذَا كَانُوا يَضْرِبُونَهُ فِي جَوْفِ كَنَائِسِهِمْ الْقَدِيمَةِ، فَإِنْ أَرَادُوا الضَّرْبَ بِهَا خَارِجًا فَلَيْسَ يَنْبَغِي أَنْ يُتْرَكُوا لِيَفْعَلُوا ذَلِكَ، لِمَا فِيهِ مِنْ مُعَارَضَةِ أَذَانِ الْمُسْلِمِينَ فِي الصُّورَةِ. (شرح السير الكبير)

Likewise, the striking of the (Christian) bell, they are not prevented from it if they are doing it inside of their long-established churches. However, if they want to do it outside, then it is not appropriate to permit them to do that. Since, it opposes the Adhaan of the Muslims. (Imam al-Sarakhsi, Sharh al-Siyar al-Kabeer).

As seen in Nusoos above Christians are prevented from reading their books loudly in places where Muslims gather. They are also prohibited from other religious practices in such a public manner. Rather they are to restrict their Kufr to themselves.

Knowing this, no Muslim could consider it permissible for Christians to enter a Masjid and be given the stage to worship whilst the congregation of Muslims observes. This goes much further than the prohibitions mentioned in the classical works of the Hanafi Madhab, so will be more strictly prohibited.

And Allah Most High Knows Best.

-Answered by Shaykh Noorud-deen Rashid (08.08.2022)

See also:
Is Islam the only religion accepted by Allah?

See also video: