You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Heresy

Context:
The term is usually used to refer to violations of important religious teachings, but is used also of views strongly opposed to any generally accepted ideas. It is used in particular in reference to Christianity, Judaism, Islam and Marxism.

Question:
What religions and idea of thought is heresy cited as being used frequently in?

Christianity, Judaism, Islam and Marxism