Does the foreign tenant's conversion of the house into a church and a place of worship for Christians constitute a breach of the three-year contract?

A Muslim is not permitted to lease property to be used as a church, whether this is stipulated in the contract or known by presumption.

If the contract was for residential use and the tenant subsequently converted it into a public church, the contract remains valid, and the landlord is entitled to the full rent. The landlord must prevent the tenant from doing so out of religious duty (hisba) and seek legal action to have the ruler prevent it. If the ruler deems it necessary to evict the tenant, then that should be done.

The lease does not become void due to the tenant's evident transgression (fisq). Rather, the tenant should be admonished for their transgression. If they desist, then all is well. Otherwise, the ruler should lease the property to someone else after evicting the tenant, if the tenant does not cease their actions.

If a dhimmi (non-Muslim citizen) leases a house for residential purposes and then converts it into a church or a public temple, the lease remains valid, and the landlord, and Muslims in general, have the right to prevent this out of religious duty (hisba).