There are many churches here. Is it permissible to go into them to hold discussions with the priests there? Is it permissible to go in just to look at them and see what the people do there?
Praise be to Allaah.
It is permissible for scholars and knowledgeable people to enter churches in order to call the people there to Islam. But we should not enter them just to look around, because there is no benefit in doing so, and there is the fear that the Muslim may be influenced by them, especially if he is ignorant about his own religion and cannot refute the confusion that they will direct towards him.
From Fataawaa al-Lajnah al-Daa’imah, 13/257