Incest is when two people who are related to each other, like a brother and sister, have sexual relations with each other. In general, Jews view incest as being wrong and harmful to the people involved, and it is against Jewish law. This law is based on the Bible which says that "You shall not uncover the nakedness of a close relative; it is your own nakedness." In other words, it is a way of protecting family relationships and making sure that people treat each other with respect.