I'm not sure which novel you're talking about but if you're talking about Reverend Hale in the crucible then your answer is that Reverend Hale's purpose in returning to Salem is to speak with the condemned prisoners and convince them that they should give false confessions rather than martyr themselves. He chooses to do this because he is tormented by guilt.
if you're talking about a different Mr. Hale then let me know and i will help you to the best of my abilities