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:
Martin_Luther

Context:
The effect of Luther's intervention was immediate. After the sixth sermon, the Wittenberg jurist Jerome Schurf wrote to the elector: "Oh, what joy has Dr. Martin's return spread among us! His words, through divine mercy, are bringing back every day misguided people into the way of the truth."

Question:
What did Schurf's letter say  Luther's return caused?

joy