Why is johns father strict on him

John's father wants his son to understand the enormous weight and responsibility it is to become a priest. As a father,and a priest, he has done his job in making his son a priest and giving him independence on what he wants to do. For instance, he left John go to the Forbidden area although it was not allowed for anyone, even priests. However, he let John know of the dangers that await him there, which proves that he is a good father.