What is the ruling of Islamic law on renting out homes in summer resorts, and to what extent is the money earned from this permissible, especially if the landlord does not know the nature of the tenants or their use of the property?

It is not permissible to rent out housing to those who disobey God therein, due to His saying, the Almighty: "And do not cooperate in sin and aggression." However, renting it out to those who do not commit forbidden acts therein is permissible. If the broker rents it out to those who disobey God therein, then it is not permissible to rent it out to him, and the money taken is unlawful. But if he does not rent it out to those who disobey God therein, then there is no harm in renting it out to him.