In "Tess of the d'Urbervilles," the quote "Remember my Lady, I was your master once! I will be your master again," is significant because it is a foreshadowing of what fate has in store for Tess.  Hardy was a fatalist and believed that things happen to people because of fate and the choices we make simply lead us to what was going to happen all a long. "At the end of the novel, after Tess dies, Hardy writes, " Justice was done, and the President of the Immortals, in Aeschylean phrase, had ended his sport with Tess." Tess was powerless to change her fate, because she had been the plaything of a malevolent universe."

When this quote is made, Alec had just told Tess that she was the cause of his backsliding.  He told her to stop waiting for Angel and come with him.  She slaps him and he responds with the quote.  He of course proves correct in his statement because later she does go to him and eventually kills him.