Al-Kāfi

Hadith 1424
mosquechristians-jews
3ـ مُحَمَّدُ بْنُ إِسْمَاعِيلَ عَنِ الْفَضْلِ بْنِ شَاذَانَ عَنْ صَفْوَانَ عَنِ الْعِيصِ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ الْسَّلام) عَنِ الْبِيَعِ وَالْكَنَائِسِ هَلْ يَصْلُحُ نَقْضُهُمَا لِبِنَاءِ الْمَسَاجِدِ فَقَالَ نَعَمْ.
3. Muhammad ibn ’Isma‘il has narrated from al-Fadl ibn Shadhan from Safwan from al-‘Is who has said the following: “I once asked abu ‘Abd Allah (a.s.), about al-Biya‘ and churches if they can be changed into Masjid. He (the Imam) said, ‘Yes, it is possible.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī