What bit of advice does Blazon give Dunstan about “being a human creature”?

Blazon tells Dunstan to figure out his obsession with Mrs. Dempster beyond the idea of her as a saint. Dunstan is a "human creature" and will go crazy if he doesn't find some closure to his ideas of Mrs. Dempster.

“You are still young enough to think that torment of the spirit is a splendid thing, a sign of a superior nature. But you are no longer a young man; you are a youngish middle-aged man, and it is time you found out that these spiritual athletics do not lead to wisdom. Forgive yourself for being a human creature, Ramezay. That is the beginning of wisdom; that is part of what is meant by the fear of God; and for you it is the only way to save your sanity. Begin now, or you will end up with your saint in the madhouse.”