What is the ruling on eating and praying in a house built with an usurious loan?

Borrowing with interest (riba) is strictly forbidden, and the one who commits it must repent to Allah and resolve not to return to it. The money borrowed with interest becomes the property of the borrower, so it is permissible for him to benefit from what he bought or built with it. There is no harm in entering his house, praying in it, and eating from his food, while also inviting him to repentance.