What is the significance of this quote in Chapter 14 of The Scarlet Letter?
“Ye that have wronged me are not sinful, save in a kind of typical illusion; neither am I fiend-like, who have snatched a fiend's office from his hands. It is our fate. Let the black flower blossom as it may! Now, go thy ways, and deal as thou wilt with yonder man."-Roger Chillingworth
On this chapter, Hester and the Physician, Hester was out in the seaside when she finally meets Chillingworth, and dares to confront him about his treatment of Dimmesdale.
She requested him that, for his own sake, he should just leave Dimmesdale alone and allow for fate to take care of whatever punishment (further punishment) the man should receive.
This, of course, was not an option for Chillingworth, whose hatred for Dimmesdale was outrageous. Therefore, Hester told him that she will expose him to Dimmesdale so that Dimmesdale can protect himself from him.
The quote "Ye that hath wronged me...." is Chillingworth's way of telling Hester "what is done is done, and had to be done because it is our fate". He realizes that he, who once was a learned and good man had been chosen by fate to endure what Hester did to him. Equally, Hester was elected by "providence" and bad luck to be tempted by Dimmesdale, and Dimmesdale weak nature tempted Hester.
That is the black flower that he is referring to: Their fates were already pre-destined (as it is commonly believed by Puritan and Calvinists of that period) and hence all that was taking place was meant to happen. Hence, he had no power to stop it.